Does anyone know what percent of boarding school applicants are wait listed at TSAO schools- specifically Andover and L’ville.
Other than the admissions office? No.
This is a difficult question to answer. Some schools waitlist up to a hundred kids, while others its just a handful. It depends on how successful the school has been in predicting yield. The waitlist is usually broken up as follows
Grade 9: boarding male/boarding female
Grade 9: day male/day female
Grade 10: boarding male/boarding female
Grade 10: day male/day female
Grade 11: boarding male/boarding female
Grade 11: day male/day female
Again the chances of getting off the waitlist are slim at most schools, unless they royally screw up the yield prediction. Over the past few years, yields have gradually been creeping up, leaving dorms filled to the brim each September. However there is a chance a school may accept less students than in previous yields in anticipation of this.
Here are two articles from the Phillipian that explains the yield rate and how it impacts housing:
http://www.old.phillipian.net/articles/2014/04/17/andover-reaches-record-high-85-percent-yield-rate
http://www.phillipian.net/articles/record-high-yield-constrains-student-housing-class-sizes-see-minor-increase