Less than 100 regular occupants

Hi Charalampos, great question! You actually need to survey 100% of occupants when there are 100 occupants or less in a building. Table 5 in the Reference Guide is pulled from this resource: http://extension.psu.edu/evaluation/tipsheets/general/how-to-determine-a-sample-size. Qualification E (beneath the table on that website) states that the entire population should be surveyed if the population is 100 people or less. This is because you can't get an appropriate sample of the population when there are so few people. Unfortunately the USGBC Alternative Transportation Calculator has an error and populates an incorrect value for row 12 when 100 or fewer occupants are entered into row 8. Using your example, if you enter 40 regular occupants, it populates 81 as the number to be surveyed, which doesn't make any sense. But, when you enter 101 occupants, the correct minimum number of surveys is populated per Table 5 (96 occupants).