You've presented an opinion, a theory that can't be substantiated under normal circumstances.
Actually the rankings do consider time to graduate and males do on average take longer to graduate. Not a theory a fact.
"Men have showed a steep decline in their on-time graduation rate, as compared to women, according to the study. From the 1945-1949 to the 1980-1984 birth cohorts, men’s on-time graduation rate declined from 66.63 percent to 60.76 percent."
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Schools try to manipulate things to improve their ranking. Vanderbilt for example sends out letters to students inviting them to apply so they can reject them and thus improving their rejection ratio. No theory as I have seen the letter.
From US News:
Graduation and retention rates (22.5 percent): The higher the proportion of first-year students who return to campus for sophomore year and eventually graduate, the better a school is apt to be at offering the classes and services that students need to succeed.
Student selectivity (12.5 percent): A school's academic atmosphere is determined in part by students' abilities and ambitions.
This measure has three components. U.S. News factors in the admissions test scores for all enrollees who took the SAT critical reading and math portions and the composite ACT (65 percent of the selectivity score).
U.S. News also considers the proportion of enrolled first-year students at National Universities and National Liberal Arts Colleges who graduated in the top 10 percent of their high school classes or the proportion of enrolled first-year students at Regional Universities and Regional Colleges who graduated in the top quarter of their classes (25 percent).
The third component is the acceptance rate or the ratio of students admitted to applicants (10 percent).
If a school told U.S. News that it included all students with scores in its reported SAT and ACT scores, then those scores were counted fully in the rankings and were not footnoted.
If less than 75 percent of the fall 2016 entering class submitted SAT and ACT scores, their test scores were discounted by 15 percent in the ranking calculations. U.S. News also used this policy in the last two editions of the rankings.
Graduation rate performance (7.5 percent): This indicator of added value shows the effect of the college's programs and policies on the graduation rate after controlling for spending and student characteristics, such as standardized test scores, high school class standing and the proportion receiving Pell Grants. U.S. News measures the difference between a school's six-year graduation rate for the class that entered in 2010 and the rate U.S. News had predicted for the class. New this year, the proportion of science, technology, engineering and math – STEM – degrees out of the total degrees granted are included for the National Universities ranking category only.
If the school's actual graduation rate for the 2010 entering class is higher than the rate U.S. News predicted for that same class, then the college is enhancing achievement or overperforming. If a school's actual graduation rate is lower than the rate that U.S. News predicted, then it is underperforming.