For months now we’ve been hearing that high-poverty schools have the largest proportion of new, inexperienced teachers and the fewest senior teachers. Mayor Bloomberg has used this claim to argue that seniority based layoffs would hurt the most disadvantaged students. Just this week, Matt DiCarlo at the Shanker Blog showed that layoffs by seniority would not disproportionately affect high-poverty schools in New York. Now it’s time to set the record straight on the distribution of experienced teachers in New York City schools.
There is no statistical evidence showing that New York City’s poorest schools have the least experienced teachers.
The scatter plot below proves this point. Each dot on the scatter plot is a New York City school. The dot depicts two pieces of information about the school – its poverty rate along the X- or horizontal axis and its average teacher experience which runs up the Y – or vertical axis. The school poverty measure is determined by the percentage of students receiving free and reduced price lunch. The teacher experience measure is determined by the approximate number of years the teacher has been teaching. Low poverty schools are located on the left side of the graph and high poverty schools are on the right. The plot shows some bunching toward the right because, as we all know, most of the city’s schools have a high percentage of students receiving free and reduced price lunch, the school measure of poverty
If senior teachers, those with the most experience, were predominantly located in the low poverty schools the dots would start at the 20 year marker on the left and trend down in a diagonal pattern to end at the lower right reaching the zero seniority, 100% poverty point. Conversely, if senior teachers were mostly located in the high poverty schools the dots would start below the 10 year seniority level on the left and trend up in a diagonal to end at the 20 year seniority, 100% poverty point.
The dots don’t show either of these patterns. Instead, they move horizontally, almost parallel, to the X-axis. The red line running through the middle of the dots, called the “fit line”, highlights this pattern. It shows that as school poverty rises average teacher seniority remains essentially the same. This means that there is no correlation between average teacher seniority and school poverty (i.e., the actual correlation is .03, close to zero.).
For those who prefer averages to correlations and graphs, let’s look at this another way. Let’s split the city’s schools into high and low poverty using New York City’s median school poverty level, 71.8%, as the dividing point (the median evenly divides the schools into two groups). 783 schools have a poverty level of 71.8% or less and 780 have a higher poverty level.
| School Poverty | Number of Schools | Average Teacher Seniority |
|---|---|---|
| 71.8% or less | 783 | 9.1 years |
| Above 71.9% | 780 | 9.0 years |
As the table above shows, average teacher experience for the low poverty group is 9.1 years and 9.0 years for the high poverty group, a difference that is not statistically significant.
Still not convinced? Then let’s zero in on the very poorest schools and set the dividing point for poverty at 85% – those with school poverty below 85% are the low poverty group and those with poverty above 85.1% are high poverty. Again, the finding is that teacher experience is not lopsided. Average teacher experience for the low poverty school group is 8.9 years versus 9.3 years for the high poverty group. Once again this is not a statistically significant difference.
| School Poverty | Number of School | Average Teacher Seniority |
|---|---|---|
| 85% or less | 1255 | 8.9 years |
| Above 85% | 307 | 9.3 years |
No matter how we define school poverty, the end result doesn’t change. Average teacher seniority is essentially the same for low and high poverty schools. The good news is that this is a good thing for New York City’s school children The bad news is that the data shows that any layoffs, will hurt all children – poor and otherwise.
6 Comments:
1 David Keck
· Mar 5, 2011 at 11:10 am
A fascinating analysis, though the issue is less than central. When the big message is that competence is not best expressed by seniority. It might be more profitable to tie experience to performance, to represent experience as strongly correlated to teacher dedication, etc.
2 Jamie
· Mar 7, 2011 at 8:46 am
I never realized that this wasn’t an issue. Looking back on the high poverty and low poverty schools it makes sense though. I saw teachers will years of experience, as well as teachers on their first year. Flash forward to my low poverty school right now… it’s the same thing!
3 Remainders: Dems pressure Cuomo to undo school cuts | GothamSchools
· Mar 7, 2011 at 7:36 pm
[...] The idea that poor schools always have the most junior teachers isn’t borne out in NYC. (Edwize) [...]
4 Online Education in America » Blog Archive » Remainders: Dems pressure Cuomo to undo school cuts
· Mar 7, 2011 at 8:47 pm
[...] The idea that poor schools always have the most junior teachers isn’t borne out in NYC. (Edwize) [...]
5 KarenS
· Mar 7, 2011 at 9:52 pm
Thank you so much for pointing this out; the truth keeps getting lost in the midst of all of the propaganda and false claims. However, the anti-seniority “reformers” still have a win-win situation for themselves. If it were true that the high poverty schools were populated mainly by new teachers, then they could claim that the vulnerable students in these schoold should not have to suffer more disruption by having their bright, motivated young teachers taken away from them–therefore end LIFO. However, if it is pointed out that the high poverty schools have a large population of senior teachers, then the deformers can say “Aha! That’s why the school is failing. Those lazy, tenured, senior teachers aren’t doing their jobs, so let’s get rid of LIFO and bring in some enthusiastic, new, young (cheap) teachers.” So, either way, it’s lose-lose for experienced, senior teachers. I myself am a highly qualified teacher with two Master’s degrees and 32 years of experience, but since my school is being phased out, I guess that I’m a “failing” teacher–along with so many of my high seniority colleagues–and many newer teachers who have also been working hard to educate and encourage all of our students
6 Joe
· Mar 7, 2011 at 10:22 pm
The problem is that there is no objective measure of teacher effectiveness. Why do we separate students by admissions tests if it is the teachers who are crucial to their performance?
The key is to give good training approved (teacher’s colleges) to college graduates who understand their subject. You wouldn’t want a “Surgery for America” surgeon to operate on you in an emergency room, yet you want college grads with no teaching training to operate on students in a classroom without any pedagogic training.