By Terry Fondow
This letter addresses the incorrect and misleading information provided in last week’s letter to the editor. First, the claim that the Antigo schools rank near the bottom of 23 districts within 60 miles and for the whole state is just plain wrong. Using the DPI Accountability Score for last year, Antigo ranks 8th of 23. In an earlier letter, I used 13 regional districts rather than 23 because I wanted the table I produced to be small enough to fit in a letter to the editor. For that list, Antigo ranked 4 of 13. 8 of 23 is not much different than 4 of 13. In fact, there is only a 4% difference so using the larger number of districts just reinforces the primary point I have been making: it is inaccurate and unfair to claim that the Antigo district is on the bottom using any reasonable measure.
Now let’s deal with the elephant in the room that others do not want to see: the impact of poverty on school achievement. “Poverty is not a primary reason for lack of academic performance,” a previous letter stated. That statement has been proven wrong by every valid major study on poverty and education since the 1950’s and I will prove it wrong again using data analyses for both the DPI Accountability Score and the test only standardized score from the website quoted in last week’s letter named Schooldigger.com. The correct statewide ranking for the Antigo district is 216 of 373, not 324 of 428 as previously claimed. There are 373 K-12 districts in Wisconsin, not 428. Beause poverty and achievement are strongly correlated, it is possible to predict a likely achievement ranking for a district based on its poverty level. Antigo scores well above its predicted ranking of 329.
For this analysis, I will use high schools because people most frequently attack Antigo High School. There are 165 high schools in Wisconsin that have more than 500 students. The proper statistic to calculate to determine if poverty and achievement scores are related is the correlation coefficient. For the DPI score, the coefficient is -.84. For the Schooldigger standardized test score, the coefficient is -.85. The correlation coefficients for both sets of data are essentially the same.
-.84 indicates a very strong relationship between poverty and achievement. The minus sign just means that as poverty increases, achievement decreases. If the coefficient were -1, that would mean that poverty is the only factor that affects achievement. Now that we know that poverty and achievement are strongly related, let’s examine just how much achievement is affected by poverty.
To do that, we first must calculate the probability that the correlation coefficient is statistically significant. Using a t-test, both sets of data indicate that the correlation coefficient of -.84 or -.85 is statistically significant at the highest level = 99.99%. For the second step, we must calculate the determination coefficient. For both sets of data, the determination coefficient is .72.
In the simplest terms possible, what all these calculations mean is that we can say with 99.99 % certainty that poverty determines 72% of the achievement score variability for schools. Poverty is not the only factor that affects achievement, but it is by far the most important. John Hattie’s research has established that the most important factor schools control that has an impact on achievement is the quality of the teacher.
Because children from a poverty background enter school with readiness deficits, it is important to measure how much children learn from one year to the next. Schooldigger does not do that. It is a one time achievement test snapshot. The DPI accountability score uses how much students have learned over multiple years in addition to the one time achievement score snap shot, which those with a solid knowledge of educational measurement consider a far more valid measure of school performance.
Finally, there are 50 high schools in Wisconsin that have more than 500 students and poverty rates above 40%. Only 10 of those schools have scores that meet or exceed the state expectation cut scores. Based on this detailed scientific analysis, what others should be encouraging the school district to do is learn more about why those 10 high schools have been able to beat the odds.
If anyone wants more details on the 10 high poverty high schools that are beating the odds or the details of the statistical calculations, just let me know by writing a comment on the Antigo Times webpage for this letter.
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