Almost all of the 66 surveys reviewed in this study were conducted disparately, and as a consequence, the data cannot be used to establish trends over a specific period of time. There are two exceptions.

The first involves two studies: one in March 2001 by the Princeton Research Associates for the Pew Research Center for the People and the Press (#38) and the other in March 1997 by Chilton Research for ABC News and Discovery News (#3). In both surveys, the same question was asked, "Regardless of what you think about the personal non-medical use of marijuana, do you think doctors should or should not be allowed to prescribe marijuana for medical purposes to treat their patients?" Seventy-three percent in the former survey stated that it "should be allowed, versus 70% in the latter. Though this slight upward shift is not greater than the margin of error (+/-4.5%), the downward movement in those who said it "should not be allowed" from 27% in 1997 to 21% in 2001 is a significant 6%.

The second trendable question comes from the Virginia Quality of Life Survey conducted by the Virginia Tech Center for Survey Research (#46, 32, 28,14, and 4). This study has reviewed the attitudes of Virginians annually since 1992 and, for trending purposes, frequently asks the same question year after year. Since 1997, the percentage of those who "Strongly agree" or "Somewhat agree" that "doctors should be legally allowed to prescribe marijuana for medical use" has risen from 69% to its 2001 level of 75%. Because this gain of six points exceeds the +/- 3.4 to 4.4% margins of error for the studies, this gain in favorable public opinion toward medicinal cannabis is significant.