State law requires public schools to provide 180 days of instruction a year, but through various exceptions, public school districts can provide fewer student days -- or, if teachers agree, more days.
In figures compiled by the Post-Gazette for 2008-09, the number of days school was in session for students in suburban Allegheny County public school districts varied from 173 at Quaker Valley High School to 186 in all Pine-Richland schools.
Pittsburgh Public Schools offered 180 days in most of its schools but operated a longer school year -- 190 days -- in eight of its schools, called accelerated learning academies.
The state Department of Education grants exceptions to the 180-day rule in certain cases, such as emergency school closings for reasons such as contagious diseases or natural disasters. The state also allows school districts to count certain professional development days -- known as Act 80 days -- as instructional days even though students don't attend.
However, the state also requires a minimum number of instructional hours: 450 for kindergarten, 900 for elementary and 990 for secondary. The whole school day doesn't count as instructional hours; some portions, such as lunch and class changes, are excluded.
The state typically doesn't budge on the number of hours. That's why, while some students were in class fewer than 180 days, none of the schools operated by county's 43 school districts fell below the minimum number of instructional hours. Dropping the hours below that point risks a portion of a district's state subsidy.
Total instructional hours in a school year in suburban Allegheny County school districts ranged from at least 924 hours for grades 1 through 6 in McKeesport Area, to 1,151 hours and 55 minutes in grades 7 and 8 in South Allegheny. That's a difference of nearly 228 hours -- or about six hours a week.
More instructional hours -- a total of 1,266 hours and 40 minutes -- were offered at the Pittsburgh's eight accelerated learning academies.
The figures don't count kindergarten programs, which can be half-time, three-fourths time or full-time.
Despite its smaller number of days, Quaker Valley still offered more instructional hours than the state minimum because its regular school day for grades 1 through 12 is among the longer ones with at least six instructional hours.
Of district schools in the county, Pittsburgh's ALAs have the most instructional hours on a regular school day, 6 hours and 40 minutes, followed by 6 hours and 35 minutes for grades 7 and 8 in South Allegheny.
Aside from kindergarten, no district provided less than 5 hours and 16 minutes of instructional time on a regular school day, the amount offered to grades 1 through 4 in Mt. Lebanon, which conducted classes for two more days than the 180-minimum.
The actual hours vary not only between school districts but within them, sometimes because of differences in early dismissals, power failures or simply scheduling.
While grades 7 and 8 in South Allegheny have one of the longest instructional days in the county, students in kindergarten through sixth grade in the same district have 55 minutes less instruction than that in each school day.
Only Clairton, Elizabeth Forward and Highlands offer the same amount of instructional time to all students in grades 1 through 12.
The hours per day for grades 7 and 8 in South Allegheny were so great that -- despite the district recording 177 days in session and five Act 80 days in 2008-09 -- its students in those two grades still had one of the highest total number of instructional hours in the county, at 1,151 hours and 55 minutes.
This past school year was a particularly challenging one to make the 180-day mark, given the harsh winter and the state Department of Education's reluctance to grant snow waivers. Pittsburgh Public Schools canceled classes so many times for weather that school was in session for only 174 days in most city schools in 2009-10.
But Pittsburgh never needed to make up student days because the district asked for -- and received -- six Act 80 days for professional development.
Even at 174 days, Pittsburgh still managed to provide at least two hours more than the state minimum number of hours and as many as 216 extra hours beyond the minimum in grades 9 through 12 at Pittsburgh CAPA (Creative and Performing Arts) High School.
But it doesn't take an unusually bad winter for Act 80 days to add up in districts trying to find time for professional development. In 2008-09, Quaker Valley declared 11 Act 80 days at its high school, which, combined with the 174 days in session, put the district above the state requirement.
Education writer Eleanor Chute: firstname.lastname@example.org or 412-263-1955.