PPP is out with a new poll on Prop 19 showing more favorable numbers than other recent polls, including Field, have shown. PPP found Prop 19 has a 52-38 lead, which is closer to the numbers SurveyUSA found (50-40 in support) than to Field (44-48 against).

PPP also found that the strongest support of California’s ethnoracial groups comes from African-Americans, who back Prop 19 by a 68-32 margin. PPP reasons that this is because of the way marijuana laws are enforced:

Despite representing 7% of CA’s population, African Americans represent 50% of prisoners in California on marijuana charges.

This too is in contrast to the Field Poll, which found African Americans opposing Prop 19 by a 40-52 margin.

What explains the contrast between PPP/SUSA and Field? Nate Silver argues that it has to do with the fact that PPP/SUSA polls are automated, whereas the Field Poll is not:

Nevertheless, it’s possible that we’re seeing some sort of Bradley effect in reverse, which I’ve reluctantly dubbed the “Broadus Effect” after the given name of the rapper Snoop Dogg, himself a frequent consumer of cannabinoid-rich products.

The original Bradley Effect, named for former Los Angeles mayor Tom Bradley, occurs when respondents in surveys are asked about socially desirable behaviors, such as being free from racial prejudice. Although the racial version of Bradley effect itself is probably a thing of the past, social desirability bias may manifest itself in other ways. Automated polls have sometimes shown relatively lower levels support for gay marriage initiatives, for instance, in states like Maine and California. Homophobia is fairly common, but has become socially undesirable; the purveyors of the automated polls have sometimes claimed that their respondents are free to be more honest when there’s not another human being on the line. If the theory holds, automated polls might also provide a setting for voters to be more honest about their feelings on marijuana use, another behavior that is probably more widespread (and privately tolerated) than it is socially acceptable. If so, that would be good news for Prop 19.

In other words, it might be the case that given the very real threat of incarceration for marijuana possession and lower levels of social acceptability, respondents are freer to be honest in responding to an automated poll than to a human being about whether they’ve used marijuana and whether they would support its legalization.

If Silver is right and there is a “Broadus effect” at work, it does raise another question: is the “Bradley effect” dead? Taken in its broadest form, are people more willing to say they’ll support marijuana legalization in response to an automated poll than they’re willing to go out and vote, or vote yes on Prop 19 when they’re filling out their ballots?

That’s a question better suited for voters and activists than the pollsters. The PPP and SUSA polls both indicate that it is possible to pass Prop 19 – if we can organize Californians to fill out their ballots for the November election. Like every other race on the ballot this year, victory or defeat is a matter of who can get out the vote.