Staples High School in Westport, as well as Weston and Darien high schools, were ranked among the 15 best high schools in Connecticut, according to U.S. News & World Report.

The magazine's list is arguably the most high-profile of the high school standings, covering about 20,000 schools across the country.

Students' "college readiness" -- their participation and performance on Advanced Placement or International Baccalaureate tests -- plays a crucial role in the rankings, which were released Tuesday.

The readiness scores of the top Fairfield County schools were: Weston High, 62.7 (fifth in the state); Staples High, 59.7 (seventh); Darien High, 59.5 (eighth); Wilton High, 58.5 (ninth); Ridgefield High, 55.7 (11th), and Joel Barlow (Redding), 53.4 (13th).

Greenwich moved from 15th to 14th in the state, posting a 53.1 college-readiness score out of a possible 100.

That number means 60 percent of the school's seniors in the 2012-13 school year took at least one AP test during high school, with 51 percent of them passing. Its readiness score was 50.6 in 2014.

"I view the U.S. News & World Report ranking as an affirmation that GHS is an academically challenging school that is generally meeting the needs of our diverse student population and preparing our graduates for college and career readiness," said Board of Education member Laura Erickson. "It is one data point. It is certainly nice to have the recognition."

The interdistrict Connecticut International Baccalaureate Academy in East Hartford was No. 1 in the state, with a readiness score of 95.3.

The School for the Talented and Gifted in Dallas was No. 1 in the country, one of 14 schools to post a readiness score of 100. The Texas school, which has competitive admissions, requires students to take at least 11 AP courses to graduate. The rankings rate schools' performances on state standardized tests.

When calculating the rankings, U.S. News also tries to determine whether students at each school are performing better than expected, a process that includes factoring in schools' numbers of "economically disadvantaged" students. In a change in methodology that is supposed to reduce volatility in the rankings, U.S. News this year lowered the threshold for schools to pass that step.

As in the past, rankings are based on data from two years prior.

In Greenwich, some say the high school's AP rates are still low for one of the highest-spending school systems in the state. They argue its numbers should be as good as or better than the top-performing schools in Fairfield and Westchester counties.