However, the magnitude of the results reported here is such that the conclusions would not change even if standard error were substantially underestimated. A fourth limitation of this analysis is that the survey population is limited to MSM who attend venues; MSM who do not attend venues may, or may not, differ from the survey population on key outcomes. For example, older MSM (who are also more likely to be HIV-infected) may be less likely to attend venues than younger MSM.