Q:

Got $2 in the mail from the Pew Research Center, is this a scam? 

Today my wife and I got a letter from the Pew Research center with a with a $2 bill enclosed.  The survey has a link to the website: http://pewresearchstudy.com with a password, asking the youngest female in the household to take a survey.  I'm a little speculative on the legitimacy of this survey and why they would give out free money in the mail.  
Has anyone encountered these types of letters before?  Is this a scam or a legitimate survey with real money being sent to us? 

A:

It's probably legitimate. 
https://www.pewresearch.org/methods/2019/02/27/growing-and-improving-pew-research-centers-american-trends-panel/

a letter of introduction inviting recipients (and specifically, the adult in the household with the next upcoming birthday) to take the online survey, information about how to take the survey, $2 in cash as a pre-incentive and a promise of a $10 post-incentive for completing the survey. 

A:

They send money to guilt you in to responding.  
Charities use this tactic too but usually with less incentive, a penny, nickle or quarter.   Pew must really want a response...

A:

Your information is worth something to them.  They're giving you part of that value in order to get the information.  This is right, good, fair and not a scam.