<p>OP, for safety, the most important consideration is acceptance rate. However, you also need to find out if a particular school, even though it has an “acceptable” admit rate, is particularly popular in the pool in which you may find yourself competing. e.g. would you be a day student, or a local boarder for a school many of your peers are trying to get in? Is your geographic region over-represented in a particular school? (Again, do some basic math) Once you have a list of schools that meet the admit rate criterion, take a closer look at them and identify the one(s) that meet or are closer to your other requirements, e.g. acdemic/extracurricular offerings, student body composition, college matriculation stats, etc. There, you got one or more safety schools.</p>
<p>Of course, safety is not a safety until you get in. Evaluate how “desperate” you want to go to a boarding school, and adjust the number and selectivity of your safety schools accordingly. Suppose you have a very strong day school option, you may not even need a safety, but if your local option is unacceptable, then be sure to include more safety schools with higher admit rate. Good luck!</p>