The effect of sunlight exposure time and pain on effectiveness estimate. The means of 490 estimates of effectiveness are plotted against both pain levels and sunlight exposure time. The pain scores are: 0 = no pain, 2 = mild pain, 5 = moderate pain, 8 = strong pain, 10 = intolerable pain. Exposure times are expressed as "multiples of 15 minutes", e.g. 1 = 15 min, 10 = 2.5 hours, 48 = 12 hours etc. The effectiveness ratings are in percent between 0 and 100. It is evident, that pain has a higher influence on the effectiveness rating than sunlight exposure time.