Retail Shopping Center Evaluation

[John Green]

I am looking at doing my first commercial real estate deal and I'm wondering if it is common to put a risk factor, based on vacancies, when evaluating the purchase price. In other words, the shopping center I am looking at is currently 100% occupied but has dealt with some vacancies over the past couple of years. When figuring NOI and Cap rate do you assume the shopping center is 100% occupied or do you put a risk factor on it, say 15%, which is about equal to one spot being vacant. Does that make sense?