It All Comes Down to a Number

Dan Lawson is the Director of Schools for Tullahoma City Schools. He sent this message and the American Educational Research Association press release to a group of Tennessee lawmakers.

I am the superintendent of Tullahoma City Schools and in light of the media coverage associated with Representative Holt and a dialogue with teachers in west Tennessee I wanted to share a few thoughts with each of who represent teachers in other districts in Tennessee. I am thankful that each of you have a commitment to service and work to cultivate a great relationship with teachers and communities that you represent.

While it is certainly troubling that the standards taught are disconcerting in that developmental appropriateness is in question by many, and that the actual test administration may be a considerable challenge due to hardware, software and capacity concerns, I think one of the major issues has been overlooked and is one that could easily address many concerns and restore a sense of confidence in many of our teachers.

Earlier this week the American Educational Research Association released a statement (see below) cautioning states “against the use of VAM for high-stakes decisions regarding educators.” It seems to me that no matter what counsel I provide, what resources I bring to assist and how much I share our corporate school district priorities, we boil our work and worth as a teacher down to a number. And for many that number is a product of how well they guess on what a school-wide number could be since they don’t have a tested area.

Our teachers are tasked with a tremendous responsibility and our principals who provide direct supervision assign teachers to areas where they are most needed. The excessive reliance on production of a “teacher number” produces stress, a lack of confidence and a drive to first protect oneself rather than best educate the child. As an example, one of my principals joined me in meeting with an exceptional middle school math teacher, Trent Stout. Trent expressed great concerns about the order in which the standards were presented (grade level) and advised that our math department was confident that a different order would better serve our students developmentally and better prepare them for higher level math courses offered in our community. He went on to opine that while he thought we (and he) would take a “hit” on our eighth grade assessment it would serve our students better to adopt the proposed timeline. I agreed. It is important to note that I was able to dialogue with this professional out of a sense of joint respect and trust and with knowledge that his status with our district was solely controlled by local decision makers. He is a recipient of “old tenure.” However, don’t mishear me, I am not requesting the restoration of “old tenure,” simply a modification of the newly enacted statute. I propose that a great deal of confidence in “listening and valuing” teachers could be restored by amending the tenure statute to allow local control rather than state eligibility.

I have teachers in my employ with no test data who guess well and are eligible for the tenure status, while I have others who guess poorly and are not eligible. Certainly, the final decision to award tenure is a local one, but local based on state produced data that may be flawed or based on teachers other than the potential nominee. Furthermore, if we opine that tenure does indeed have value, I am absolutely lost when I attempt to explain to new teachers that if they are not eligible for tenure I may employ them for an unlimited number of added contracts but if they are eligible based on their number and our BOE decides that they will not award tenure to anyone I am compelled to non-renew those who may be highly effective teachers. The thought that statue allows me to reemploy a level 1 teacher while compelling me to non-renew a level 5 teacher seems more than a bit ironic and ridiculous.

I greatly appreciate your service to our state and our future and would love to see an extensive dialogue associated to the adoption of Common Sense.

The American Educational Research Association Statement on Value-Added Modeling:

In a statement released today, the American Educational Research Association (AERA) advises those using or considering use of value-added models (VAM) about the scientific and technical limitations of these measures for evaluating educators and programs that prepare teachers. The statement, approved by AERA Council, cautions against the use of VAM for high-stakes decisions regarding educators.

In recent years, many states and districts have attempted to use VAM to determine the contributions of educators, or the programs in which they were trained, to student learning outcomes, as captured by standardized student tests. The AERA statement speaks to the formidable statistical and methodological issues involved in isolating either the effects of educators or teacher preparation programs from a complex set of factors that shape student performance.

“This statement draws on the leading testing, statistical, and methodological expertise in the field of education research and related sciences, and on the highest standards that guide education research and its applications in policy and practice,” said AERA Executive Director Felice J. Levine.

The statement addresses the challenges facing the validity of inferences from VAM, as well as specifies eight technical requirements that must be met for the use of VAM to be accurate, reliable, and valid. It cautions that these requirements cannot be met in most evaluative contexts.

The statement notes that, while VAM may be superior to some other models of measuring teacher impacts on student learning outcomes, “it does not mean that they are ready for use in educator or program evaluation. There are potentially serious negative consequences in the context of evaluation that can result from the use of VAM based on incomplete or flawed data, as well as from the misinterpretation or misuse of the VAM results.”

The statement also notes that there are promising alternatives to VAM currently in use in the United States that merit attention, including the use of teacher observation data and peer assistance and review models that provide formative and summative assessments of teaching and honor teachers’ due process rights.

The statement concludes: “The value of high-quality, research-based evidence cannot be over-emphasized. Ultimately, only rigorously supported inferences about the quality and effectiveness of teachers, educational leaders, and preparation programs can contribute to improved student learning.” Thus, the statement also calls for substantial investment in research on VAM and on alternative methods and models of educator and educator preparation program evaluation.

The AERA Statement includes 8 technical requirements for the use of VAM:

  1. “VAM scores must only be derived from students’ scores on assessments that meet professional standards of reliability and validity for the purpose to be served…Relevant evidence should be reported in the documentation supporting the claims and proposed uses of VAM results, including evidence that the tests used are a valid measure of growth [emphasis added] by measuring the actual subject matter being taught and the full range of student achievement represented in teachers’ classrooms” (p. 3).
  2. “VAM scores must be accompanied by separate lines of evidence of reliability and validity that support each [and every] claim and interpretative argument” (p. 3).
  3. “VAM scores must be based on multiple years of data from sufficient numbers of students…[Related,] VAM scores should always be accompanied by estimates of uncertainty to guard against [simplistic] overinterpretation[s] of [simple] differences” (p. 3).
  4. “VAM scores must only be calculated from scores on tests that are comparable over time…[In addition,] VAM scores should generally not be employed across transitions [to new, albeit different tests over time]” (AERA Council, 2015, p. 3).
  5. “VAM scores must not be calculated in grades or for subjects where there are not standardized assessments that are accompanied by evidence of their reliability and validity…When standardized assessment data are not available across all grades (K–12) and subjects (e.g., health, social studies) in a state or district, alternative measures (e.g., locally developed assessments, proxy measures, observational ratings) are often employed in those grades and subjects to implement VAM. Such alternative assessments should not be used unless they are accompanied by evidence of reliability and validity as required by the AERA, APA, and NCME Standards for Educational and Psychological Testing” (p. 3).
  6. “VAM scores must never be used alone or in isolation in educator or program evaluation systems…Other measures of practice and student outcomes should always be integrated into judgments about overall teacher effectiveness” (p. 3).
  7. “Evaluation systems using VAM must include ongoing monitoring for technical quality and validity of use…Ongoing monitoring is essential to any educator evaluation program and especially important for those incorporating indicators based on VAM that have only recently been employed widely. If authorizing bodies mandate the use of VAM, they, together with the organizations that implement and report results, are responsible for conducting the ongoing evaluation of both intended and unintended consequences. The monitoring should be of sufficient scope and extent to provide evidence to document the technical quality of the VAM application and the validity of its use within a given evaluation system” (AERA Council, 2015, p. 3).
  8. “Evaluation reports and determinations based on VAM must include statistical estimates of error associated with student growth measures and any ratings or measures derived from them…There should be transparency with respect to VAM uses and the overall evaluation systems in which they are embedded. Reporting should include the rationale and methods used to estimate error and the precision associated with different VAM scores. Also, their reliability from year to year and course to course should be reported. Additionally, when cut scores or performance levels are established for the purpose of evaluative decisions, the methods used, as well as estimates of classification accuracy, should be documented and reported. Justification should [also] be provided for the inclusion of each indicator and the weight accorded to it in the evaluation process…Dissemination should [also] include accessible formats that are widely available to the public, as well as to professionals” ( p. 3-4).

The bottom line:  Tennessee’s use of TVAAS in teacher evaluations is highly problematic.

More on TVAAS:

Not Yet TNReady

The Worst Teachers

Validating the Invalid

More on Peer Assistance and Review:

Is PAR a Worthy Investment?

For more on education politics and policy in Tennessee, follow @TNEdReport


The Worst Teachers?

“There is a decently large percentage of teachers who are saying that they feel evaluation isn’t fair,” he (state data guru Nate Schwartz) said. “That’s something we need to think about in the process we use to evaluate teachers … and what we can do to make clear to teachers how this process works so they feel more secure about it.”

This from a story about the recently released 2015 Educator Survey regarding teacher attitudes in Tennessee.

One reason teachers might feel the evaluation is unfair is the continued push to align observation scores with TVAAS (Tennessee Value-Added Assessment System) data – data that purportedly captures student growth and thereby represents an indicator of teacher performance.

From WPLN:

Classroom observation scores calculated by principals should roughly line up with how a teacher’s students do on standardized tests. That’s what state education officials believe. But the numbers on the state’s five point scale don’t match up well.

“The gap between observation and individual growth largely exists because we see so few evaluators giving 1s or 2s on observation,” the report states.

“The goal is not perfect alignment,” Department of Education assistant commissioner Paul Fleming says, acknowledging that a teacher could be doing many of the right things at the front of the class and still not get the test results to show for it. But the two figures should be close.

In order to be better at aligning observation scores with TVAAS scores, principals could start by assigning lower scores to sixth and seventh grade teachers. At least, that’s what the findings of a study by Jessica Holloway-Libell published in June in the Teachers College Record suggest.

Holloway-Libell studied value-added scores assigned to individual schools in 10 Tennessee districts — Urban and suburban — and found:

In ELA in 2013, schools were, across the board, much more likely to receive positive value-added scores for ELA in fourth and eighth grades than in other grades (see Table 1). Simultaneously, districts struggled to yield positive value-added scores for their sixth and seventh grades in the same subject-areas. Fifth grade scores fell consistently in the middle range, while the third-grade scores varied across districts

Table 1. Percent of Schools that had Positive Value-Added Scores in English/language arts by Grade and District (2013) (Districts which had less than 25% of schools indicate positive growth are in bold)
District      Third      Fourth    Fifth     Sixth     Seventh      Eighth
Memphis      41%       43%        45%      19%        14%           76%
Nashville      NA        43%        28%      16%        15%           74%
Knox             72%       79%        47%      14%         7%            73%
Hamilton     38%      64%        48%      33%      29%            81%
Shelby           97%     76%         61%       6%        50%            69%
Sumner         77%     85%         42%       17%      33%            83%
Montgomery NA      71%         62%       0%        0%              71%
Rutherford     83%   92%         63%      15%     23%             85%
Williamson    NA      88%        58%      11%      33%           100%
Murfreesboro NA     90%        50%     30%     NA              NA

SOURCE: Teachers College Record, Date Published: June 08, 2015 ID Number: 17987, Date Accessed: 7/27/2015

In examining three-year averages, Holloway-Libell found:

The three-year composite scores were similar except even more schools received positive value-added scores for the fifth and eighth grades. In fact, in each of the nine districts that had a composite score for eighth grade, at least 86% of their schools received positive value-added scores at the eighth-grade level.

By contrast, results in math were consistently positive across grade level and district type:

In particular, the fourth and seventh grade-level scores were consistently higher than those of the third, fifth, sixth, and eighth grades, which illustrated much greater variation across districts. The three-year composite scores were similar. In fact, a majority of schools across the state received positive value-added scores in mathematics across all grade levels.

So, what does this mean?

Well, it could mean that Tennessee’s 6th and 7th grade ELA teachers are the worst in the state. Or, it could mean that math teachers in Tennessee are better teachers than ELA teachers. Or, it could mean that 8th grade ELA teachers are rock stars.

Alternatively, one might suspect that the results of Holloway-Libell’s analysis suggest both grade level and subject matter bias in TVAAS.

In short, TVAAS is an unreliable predictor of teacher performance. Or, teaching 6th and 7th grade students reading is really hard.

Holloway-Libell’s findings are consistent with those of Lockwood and McCaffrey (2007) published in the Journal of Educational Measurement:

The researchers tested various VAM models and found that teacher effect estimates changed significantly based on both what was being measured AND how it was measured.

That is, it’s totally consistent with VAM to have different estimates for math and ELA teachers, for example. Math questions are often asked in a different manner than ELA questions and the assessment is covering different subject matter.

So, TVAAS is like other VAM models in this respect. Which means, as Lockwood and McCaffrey suggest, “caution is needed when interpreting estimated teacher effects” when using VAM models (like TVAAS).

In other words: TVAAS is not a reliable predictor of teacher performance.

Which begs the question: Why is the Tennessee Department of Education attempting to force correlation between observed teacher behavior and a flawed, unreliable measure of teacher performance? More importantly, why is such an unreliable measure being used to evaluate (and in some districts, reward with salary increases) teachers?

Don’t Tennessee’s students and parents deserve a teacher evaluation system that actually reveals strong teaching and provides support for teachers who need improvement?

Aren’t Tennessee’s teachers deserving of meaningful evaluation based on sound evidence instead of a system that is consistent only in its unreliability?

The American Statistical Association has said value-added models generally are unreliable as predictors of teacher performance. Now, there’s Tennessee-specific evidence that suggests strongly that TVAAS is biased, unreliable, and not effective as a predictor of teacher performance.

Unless, that is, you believe that 6th and 7th grade ELA teachers are our state’s worst.

For more on education politics and policy in Tennessee, follow @TNEdReport




Reform is Working

That’s the message from the Tennessee Department of Education based on recently released TCAP results and an analysis of the data over time.

You can see for yourself here and here.

The one area of concern is reading, but overall, students are performing better than they were when new TCAP tests were started and standards were raised.

Here’s the interesting thing: This is true across school districts and demographic subgroups. The trend is positive.

Here’s something else: A similar trend could be seen in results before the change in the test in 2009.

Tennessee students were steadily making gains. Teachers and schools were hitting the mark set for them by policymakers. This in an age of collective bargaining for teachers and no TVAAS-based evaluation or pay schemes.

When the standards were made higher — certainly a welcome change — teachers again hit the mark.

Of course, since the standards change, lots of other reforms have taken place. Most of these have centered around teachers and the incorporation of TVAAS in teacher evaluation and even pay schemes. The State Board of Education even gutted the old state salary schedule to promote pay differentiation, ostensibly based on TVAAS scores.

But does pay for TVAAS actually lead to improved student outcomes as measured by TVAAS?

Consider this comparison of Putnam County and Cumberland County. Putnam was one of the original TIF recipients and among the first to develop a pay scheme based on teacher evaluations and TVAAS.

Putnam’s 2014 TVAAS results are positive, to be sure. But neighboring Cumberland County (a district that is demographically similar and has a similar assortment of schools) also shows positive TVAAS results.  Cumberland relies on the traditional teacher pay scale. From 2012-13 to 2013-14, Putnam saw a 50% increase in the number of categories (all schools included) in which they earned TVAAS scores of 5. So did Cumberland County.

Likewise, from 2012-13 to 2013-14, Putnam saw a 13% decline in the number of categories in which they earned TVAAS scores below a 3. In Cumberland County, the number was cut by 11%.

This is one example over a two-year cycle. New district level results for 2015 will soon be available and will warrant an update. But, it’s also worth noting that these results track results seen in Denver in analysis of their ProComp pay system. Specifially, University of Colorado’s Denver ProComp Evaluation Report (2010-2012) finds little impact of ProComp on student achievement, or on teachers’ professional practices, including their teaching practices or retention.

The Putnam-Cumberland initial analysis tracks with that of the ProComp studies: Teacher performance pay, even if devised in conjunction with teacher groups, cannot be said to have a significant impact on student performance over time.

So, prior to 2008, student academic achievement as measured by Tennessee standardized tests showed steady improvement over time. This occurred in an environment with no performance pay. Again from 2009-2015, across districts and demographic groups, student achievement is improving. Only a small number of Tennessee districts have performance pay schemes — so, that alone would indicate that performance pay is not driving improved student outcomes.  Then, a preliminary comparison of two districts suggests that both performance pay and non-performance pay districts see significant (and similar) TVAAS gains.

Reform may be working — but it may not be the reform the reformers want to push.

For more on education politics and policy in Tennessee, follow @TNEdReport

Is John Oliver Reading TN Ed Report?

John Oliver recently took on the issue of standardized testing and it sounds like he’s been reading Tennessee Education Report. In 18 brilliant minutes, he hits on a number of topics covered here time and again.

Oliver discussed teacher merit pay, the recruiting tactics of testing companies, value-added assessment, and testing transparency.

Back in 2013, Tennessee’s State Board of Education moved toward merit pay based on value-added data.

This year, while adding nearly $100 million to the pot for teacher compensation, Governor Haslam continued a push for merit pay.

While Oliver noted that Pearson recruits test scorers on Craigslist, Tennessee’s new testing vendor, Measurement, Inc. uses the same practice.

And of course, there’s the issue of value-added assessment — in Tennessee, called TVAAS. While it yields some interesting information, it’s not a reliable predictor of teacher performance and it’s going to be even more unreliable going forward, due to the shift from TCAP to TNReady. Here’s what we’ve learned from TVAAS in Tennessee:

In fact, this analysis demonstrates that the difference between a value-added identified “great” teacher and a value-added identified “average” teacher is about $300 in earnings per year per student.  So, not that much at all.  Statistically speaking, we’d call that insignificant.  That’s not to say that teachers don’t impact students.  It IS to say that TVAAS data tells us very little about HOW teachers impact students.

Surprisingly, Tennessee has spent roughly $326 million on TVAAS and attendant assessment over the past 20 years. That’s $16 million a year on a system that is not yielding much useful information.

And then there’s testing transparency. Oliver points out that it’s difficult if not impossible to get access to the actual test questions. In fact, Tennessee’s testing vendor, Measurement, Inc., has a contract with Utah’s testing vendor that involves a fine if test questions are revealed — $5000 per question:

The contract further notes that any release of the questions either by accident or as required by law, will result in a fee of $5000 per test item released. That means if Tennessee wants to release a bank of questions generated from the Utah test and used for Tennessee’s assessment, the state would pay $5000 per question.

Here’s the clip from John Oliver:


For more on education politics and policy in Tennessee, follow @TNEdReport


The End of an Era

Over at Bluff City Ed, Jon Alfuth celebrates the end of the EOC testing era. Those tests will be replaced with TNReady next year.

Alfuth notes that there are many challenges with the current testing regime, including gaming the system and misalignment with current standards.

Here’s what he says he hopes the new tests provide:

First, I’d personally like to see aligned pre- and formative assessments to allow teachers to track tests throughout the year. These could be given to the districts and used to develop a benchmark for where students are starting and track their progress throughout the year. These should be designed by Measurement Inc. to ensure close alignment to the actual test.

Second, we need to see shorter tests. Asking students to sit for between 2 to 4 three hour assessments in a four day period is a lot, and it does stress kids out. I’d like to see the number of questions reduced on the new TNReady assessments to reflect this reality.

Third, we need better special education and special needs accommodations. I’m not a special education teacher myself, but from talking to some of my colleagues my understanding is that the accommodations for the EOC regime aren’t the greatest. Hopefully a technologically advanced test like TNReady (it can be given on paper or on a computer) could include better accommodations for kids with special needs. I also hope it makes automatic adjustments for students who, say, speak English as a second language.

Fourth, we need to see a substantial increase of resources aligned to the new assessments and SOON. Teachers need time to internalize the format at the types of questions that students will be asked to complete on the new assessments. That was one of the failings of PARCC and one reason I believe we no longer have it in Tennessee – teachers didn’t have enough supporting resources and backed off support for the assessment. Lets hope that TNReady doesn’t make the same mistake.

More on TNReady:

TNReady to Borrow Questions from Utah

Transition to TNReady Creates TVAAS Problems

For more on education politics and policy, follow @TNEdReport

A Little Less Bad

From a story in Chalkbeat:

Tennessee’s teacher evaluation system is more accurate than ever in measuring teacher quality…

That’s the conclusion drawn from a report on the state’s teacher evaluation system conducted by the State Department of Education.

The idea is that the system is improving.

Here’s the evidence the report uses to justify the claim of an improving evaluation system:

1) Teacher observation scores now more closely align with teacher TVAAS scores — TVAAS is the value-added modeling system used to determine a teacher’s impact on student growth

2) More teachers in untested subjects are now being evaluated using the portfolio system rather than TVAAS data from students they never taught

On the second item, I’d note that previously, 3 districts were using the a portfolio model and now 11 districts use it. This model allows related-arts teachers and those in other untested subjects to present a portfolio of student work to demonstrate that teacher’s impact on growth. The model is generally applauded by teachers who have a chance to use it.

However, there are 141 districts in Tennessee and 11 use this model. Part of the reason is the time it takes to assess portfolios well and another reason is the cost associated with having trained evaluators assess the portfolios. Since the state has not (yet) provided funding for the use of portfolios, it’s no surprise more districts haven’t adopted the model. If the state wants the evaluation model to really improve (and thereby improve teaching practice), they should support districts in their efforts to provide meaningful evaluation to teachers.

A portfolio system could work well for all teachers, by the way. The state could move to a system of project-based learning and thus provide a rich source of material for both evaluating student mastery of concepts AND teacher ability to impact student learning.

On to the issue of TVAAS and observation alignment. Here’s what the report noted:

Among the findings, state education leaders are touting the higher correlation between a teacher’s value-added score (TVAAS), which estimates how much teachers contribute to students’ growth on statewide assessments, and observation scores conducted primarily by administrators.

First, the purpose of using multiple measures of teacher performance is not to find perfect alignment, or even strong correlation, but to utilize multiple inputs to assess performance. Pushing for alignment suggests that the department is actually looking for a way to make TVAAS the central input driving teacher evaluation.

Advocates of this approach will tell suggest that student growth can be determined accurately by TVAAS and that TVAAS is a reliable predictor of teacher performance.

I would suggest that TVAAS, like most value-added models, is not a significant differentiator of teacher performance. I’ve written before about the need for caution when using value-added data to evaluate teachers.

More recently, I wrote about the problems inherent in attempting to assign growth scores when shifting to a new testing regime, as Tennessee will do next year when it moves from TCAP to TNReady. In short, it’s not possible to assign valid growth scores when comparing two entirely different tests.  Researchers at RAND noted:

We find that the variation in estimated effects resulting from the different mathematics achievement measures is large relative to variation resulting from choices about model specification, and that the variation within teachers across achievement measures is larger than the variation across teachers. These results suggest that conclusions about individual teachers’ performance based on value-added models can be sensitive to the ways in which student achievement is measured.
These findings align with similar findings by Martineau (2006) and Schmidt et al (2005)
You get different results depending on the type of question you’re measuring.

The researchers tested various VAM models (including the type used in TVAAS) and found that teacher effect estimates changed significantly based on both what was being measured AND how it was measured. 

And they concluded:

Our results provide a clear example that caution is needed when interpreting estimated teacher effects because there is the potential for teacher performance to depend on the skills that are measured by the achievement tests.

So, even if you buy the idea that TVAAS is a significant differentiator of teacher performance, drawing meaningful conclusions from next year’s TNReady simply is not reliable.

The state is touting improvement in a flawed system that may now be a little less bad.  And because they insist on estimating growth from two different tests with differing methodologies, the growth estimates in 2016 will be unreliable at best. If they wanted to improve the system, they would take two to three years to build growth data based on TNReady — that would mean two t0 three years of NO TVAAS data in teacher evaluation.

Alternatively, the state could move to a system of project-based learning and teacher evaluation and professional development based on a Peer Assistance and Review Model. Such an approach would be both student-centered and result in giving teachers the professional respect they deserve. It also carries a price tag — but our students are worth doing the work of both reallocating existing education dollars and finding new ways to invest in our schools.

For more on education politics and policy in Tennessee, follow @TNEdReport




Validating the Invalid?

The Tennessee House of Representatives passed legislation today (HB 108) that makes changes to current practice in teacher evaluation as Tennessee transitions to its new testing regime, TNReady.

The changes adjust the percentage of a teacher’s evaluation that is dependent on TVAAS scores to 10% next year, 20% the following year, and back to the current 35% by the 2017-18 academic year.

This plan is designed to allow for a transition period to the new TNReady tests which will include constructed-response questions and be aligned to the so-called Tennessee standards which match up with the Common Core State Standards.

Here’s the problem: There is no statistically valid way to predict expected growth on a new test based on the historic results of TCAP. First, the new test has (supposedly) not been fully designed. Second, the test is in a different format. It’s both computer-based and it contains constructed-response questions. That is, students must write-out answers and/or demonstrate their work.

Since Tennessee has never had a test like this, it’s impossible to predict growth at all. Not even with 10% confidence. Not with any confidence. It is the textbook definition of comparing apples to oranges.

Clearly, legislators feel like at the very least, this is an improvement. A reasonable accommodation to teachers as our state makes a transition.

But, how is using 10% of an invalid number a good thing? Should any part of a teacher’s evaluation be made up of a number that reveals nothing at all about that teacher’s performance?

While value-added data alone is a relatively poor predictor of teacher performance, the value-added estimate used next year is especially poor because it is not at all valid.

But, don’t just take my word for it. Researchers studying the validity of value-added measures asked whether value-added gave different results depending on the type of question asked. Particularly relevant now because Tennessee is shifting to a new test with different types of questions.

Here’s what Lockwood and McCaffrey (2007) had to say in the Journal of Educational Measurement:

We find that the variation in estimated effects resulting from the different mathematics achievement measures is large relative to variation resulting from choices about model specification, and that the variation within teachers across achievement measures is larger than the variation across teachers. These results suggest that conclusions about individual teachers’ performance based on value-added models can be sensitive to the ways in which student achievement is measured.
These findings align with similar findings by Martineau (2006) and Schmidt et al (2005)
You get different results depending on the type of question you’re measuring.

The researchers tested various VAM models (including the type used in TVAAS) and found that teacher effect estimates changed significantly based on both what was being measured AND how it was measured. 

And they concluded:

Our results provide a clear example that caution is needed when interpreting estimated teacher effects because there is the potential for teacher performance to depend on the skills that are measured by the achievement tests.

If you measure different skills, you get different results. That decreases (or eliminates) the reliability of those results. TNReady is measuring different skills in a different format than TCAP. It’s BOTH a different type of test AND a test on different standards. Any value-added comparison between the two tests is statistically suspect, at best. In the first year, such a comparison is invalid and unreliable. As more years of data become available, it may be possible to make some correlation between past TCAP results and TNReady scores.

Or, if the state is determined to use growth scores (and wants to use them with accuracy), they will wait several years and build completely new growth models based on TNReady alone. At least three years of data would be needed in order to build such a model.

It seems likely that the Senate will follow the House’s lead on Monday and overwhelmingly support the proposed evaluation changes. But in doing so, they should be asking themselves if it’s really ok to base any part of a teacher’s evaluation on numbers that reliably predict nothing.

More on Value-Added:

Real World Harms of Value-Added Data

Struggles with Value-Added Data


Is THAT even legal?

That’s the question the Tennessee Education Association is asking about the use of value-added data (TVAAS) in teacher evaluations.

The TEA, joining with the National Education Association, has filed a lawsuit challenging the constitutionality of Tennessee’s use of TVAAS data in teacher evaluations.

According to a press release, TEA is specifically concerned about teachers who receive value-added scores based on students they have never taught. A significant number of Tennessee teachers currently receive a portion of their evaluation score based on TVAAS scores from school-wide or other data, meaning teachers are graded based on students they’ve never taught.

The release states:

More than half of the public school teachers in Tennessee receive evaluations that are based substantially on standardized test scores of students in subjects they do not teach. The lawsuit seeks relief for those teachers from the arbitrary and irrational practice of measuring their effectiveness with statistical estimates based on standardized test scores from students they do not teach and may have never met. 

While Governor Haslam is proposing that the legislature reduce the impact of TVAAS scores on teacher evaluations during the state’s transition to new standardized tests, his proposal does not address the issues of statistical validity with the transition. There is no way to determine how TCAP scores will interface with the scores from a test that has not even been developed yet. To hold teachers accountable for data generated in such an unreliable fashion is not only statistically suspect, it’s disrespectful.

Finally, it’s worth noting that value-added data doesn’t do much in terms of differentiating teacher performance. Of course, even if it did, holding teachers accountable for students they don’t teach defies logic.

For more on education politics and policy in Tennessee, follow @TNEdReport


Do Your Job, Get Less Money

Over at Bluff City Ed, there’s an article analyzing the new pay scale for teachers in Shelby County Schools. The scale is weighted toward TVAAS data and the evaluation rubric, which rates teachers on a scale of 1-5, 1 being significantly below expectations and 5 being significantly above. A teacher earning a 3 “meets expectations.” That means they are doing their job and doing it well.

Jon does a nice job of breaking down what it means to “meet expectations.” But, here’s the problem he’s highlighting:  Teachers who meet expectations in the new system would see a reduction in their annual step raise. That’s right: They do their job and meet the district’s performance expectations and yet earn LESS than they would with the current pay system.

Jon puts it this way:

But what the district outlines as meeting expectations exemplifies a hardworking and effective educator who is making real progress with their community, school and students. If a teacher is doing all these things, I believe that they should be in line for a yearly raise, not a cut. At its core, this new merit pay system devalues our teachers who fulfill their professional duties in every conceivable way.

I would add to this argument that to the extent that the new pay scale is based on a flawed TVAAS system which provides minimal differentiation among teachers, it is also flawed. Value-added data does not reveal much about the differences in teacher performance. As such, this data shouldn’t weigh heavily (or at all) in performance pay schemes.

Systems like Shelby County may be better served by a pay scale that starts teachers at a high salary and rewards them well over time. Increasing pay overall creates the type of economic incentives that both attract strong teachers and encourage school systems to develop talent and counsel out low performers.

Shelby County can certainly do more to attract and retain strong teaching talent. But the new pay scale is the wrong way to achieve that goal.

For more on education politics and policy in Tennessee, follow @TNEdReport


Little Value Added?


That’s the conclusion teacher Jon Alfuth draws about Governor Bill Haslam’s recently announced changes to teacher evaluation and support.

Alfuth notes with frustration that Haslam appears happy to support teachers in ways that don’t involve any new money.

Reducing the weight given TVAAS on a teacher’s evaluation, for example, doesn’t cost anything. Adding a few teachers to a “cabinet” to give feedback on tests is welcome change, but also doesn’t carry a price tag.

Haslam’s changes still unfairly assess teachers in non-tested subjects, in Alfuth’s view:

While reducing the percentage from 25 to 15 percent achievement data for non-EOC teachers is a step in the right direction, I don’t feel that it goes far enough. I personally think it’s unfair to use test scores from courses not taught by a teacher in their evaluation given the concerns surrounding the reliability of these data systems overall.

And, Alfuth says, the financial support teachers and schools need is simply not discussed:

Consider the teacher salary discussion we’ve been having here in Tennessee. This is something that Tennessee Teachers have been clamoring for and which the governor promised but then went back on this past spring. There’s no mention of other initiatives that would require extra funding, such as BEP2.0, which would provide millions of additional dollars to our school districts across the state and do much to help teachers. There’s also no mention of expanding training Common Core trainng, which is essential if we’re going to continue to enable teachers to be successful when the three year phase in of growth scores winds down.

In short, while the proposed changes are step forward, at least in the view of one teacher, much more can be done to truly support teachers and their students.

More on the importance of investing in teacher pay:

Notes on Teacher Pay

More on the state’s broken school funding formula, the BEP:

A BEP Lawsuit?

The Broken BEP

What is BEP 2.0?

For more from Jon Alfuth and education issues in Memphis, follow @BluffCityEd

For more on education politics and policy in Tennessee, follow @TNEdReport