To avoid having ties in the numerical rankings, the primary tiebreaker, which measures the absolute level of success in passing AP or IB tests, was the unrounded quality-adjusted exams per test-taker (the number of exams that received passing scores divided by the number of students who took and passed at least one exam). This was used as the first tiebreaker since U.S. News weights performance on the AP and IB tests three times higher than the simple AP or IB test participation rate.
If necessary, a second tiebreaker used was exams per test-taker, which was the average number of AP and/or IB exams passed per test-taker (the total exams taken divided by the number of test-takers).
All tiebreakers used were unrounded values carried out to many decimal places.
Analysts from AIR, who implemented U.S. News's comprehensive rankings methodology, used several indicators to determine which high schools met the three-step tiered criteria as outlined in the Best High Schools rankings methodology. These indicators include:
• Step 1: Overall performance of students on state tests
Performance index for each high school in each state (all students)
An index that measures the mastery of state tests, with full credit awarded to proficient scores, additional credit awarded to more advanced scores and partial credit awarded to scores approaching proficient. This performance index was computed for each high school based on student performance on 2010-2011 state reading and mathematics assessments.
Economically disadvantaged students as a percent of total enrollment
A measure of student poverty, which is typically the percent of each high school's total enrollment receiving free or reduced-price lunch. This used federal data from the U.S. Department of Education's website.
Risk-adjusted performance index
Each high school's residual measured the degree to which a high school differed from its statistically expected performance on reading and mathematics assessments, given the proportion of economically disadvantaged students.
High schools with risk-adjusted performance index values at or above the upper threshold of the performance zone of one-half of a standard deviation were considered performing beyond expectations and passed Step 1, according to U.S. News, and advanced to Step 2.
• Step 2: Identify high schools that performed better than the state average for their least advantaged students
Combined reading and mathematics proficiency rate for disadvantaged student subgroups for each high school
Reading and mathematics proficiency rate is a weighted average of the percentage of students for each group at or above the proficient level.
State average combined reading and mathematics proficiency rate for disadvantaged student subgroups
A weighted state average for the disadvantaged student subgroups was calculated using student subgroup performance across all high schools in the state.
Disadvantaged students performance gap differential
The differential between a school's disadvantaged student performance index and the state average for that index. Only values greater than zero meet the criteria for selection.
Values greater than zero indicated that a high school's disadvantaged student subgroups outperformed the state average. Values lower than or equal to zero meant that a high school's disadvantaged student subgroups performed no better or worse than the state average.
High schools that do as well as or better than the state average
High schools with disadvantaged student subgroups that performed as well as or better than the state average advanced to Step 3. That is, all high schools that had a value of zero or higher for the disadvantaged student proficiency gap differential passed Step 2.