Methodological rigor with internet samples: new ways to reach underrepresented populations.

We present several rigorous methods for sampling difficult-to-reach and empirically underrepresented populations via the Internet. The methodology's representativeness was tested by comparing the demographics of a small sample of 82 lesbian and bisexual females with a much larger Gallup Organization sample of the general population (n > 1,000) obtained via random digit dialing. Compared to the latter poll, the rigorous sampling designs developed for the Internet were found to be significantly more robust and equally representative of the U.S. general population. The Gallup Organization reached a sample more representative of the age distribution of the United States. The Internet sample reached a sample more representative of the population, with less education, lower incomes, and a broad spectrum of ethnic diversity. The samples were equally effective in representing the distribution of the population with rural and urban residence.