NEW YORK  – A recent report on academic achievement in New York City schools confirms what Mayor Michael Bloomberg has suspected all along: Students in smaller schools will be more successful than their peers.

The study, conducted by the research group MDRC, found that students at the city’s smaller high schools are more likely to graduate on time and be better prepared for college than students at more traditional larger schools, reports radio station WNYC.

The findings only strengthen Mayor Bloomberg’s case in his ongoing feud with the United Federation of Teachers, the city’s teachers union. UFT President Michael Mulgrew has argued that smaller schools take fewer kids with special needs and learning challenges, but MDRC President Gordon Berlin says that’s generally not the case.

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The city has created more than 200 smaller high schools since Bloomberg took office and has closed many larger high schools, according to WYNC.

The study was produced by a team of independent researchers who interviewed the principals of various high schools, compared test scores and monitored graduation rates of students who entered the ninth grade in 2004-2006.

Their findings were significant.

On average, the four-year graduation rate for students in small schools was 74.6 percent compared to 65.1 percent in the control group, reports the news story.  The average graduation rate for all students from 2004-2006 was 70.4 percent for small schools and 60.9 percent for the other schools.

The researchers also spoke with 25 small school principals who credited smaller and more personalized environments as major factors for the higher graduation rates.

The report also found that students who attended smaller schools were more likely to be better prepared for college. Forty percent of the small school students scored a 75 or better on the English Regents exam, while only one-third of the traditional school control group scored as well, according to the news story.

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“It seems pretty clear now that these small high schools are much, much stronger than some of the traditional high schools,” Berlin was quoted as saying. “So we came away very impressed by the size of the result.”

Berlin said that the findings were especially significant because the city’s average high school graduation rate increased during this time period, but the small schools continued to do better than average, according to the story.

The study comes at a pivotal time in the city’s mayoral race, in which several candidates are vying to replace Bloomberg next year. A number of candidates have been pandering to union interests, stating that they would prefer to spend money trying to improve struggling schools around rather than replace them with smaller schools or charter schools.

The research group that produced the study is politically independent, so Berlin wouldn’t comment on whether the city should invest further to smaller schools.

But he did offer some sound advice:

“Right now, if you are basing your decision purely on the evidence, what we know is that the small school strategy is effective and what we hope is that we can do better on school turnaround. That’s the difficult choice that faces high school reform.”