Why is it that my federal return went from $1508 to $431 after entering my wife's education info, even when it says she earned a $1,167 credit?

It could be due to many reasons.  Without seeing your tax return, it is hard to say.  It could be you did not withhold enough taxes with your employer or you might not have answered some of the questions correctly thus miss certain credits and deductions.  Would you like to have somebody to look over your return?

I would suggest you consider our new product / features TurboTaxLive to file your 2019 taxes.  This way you could have one of our tax professionals to review your tax forms. 

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@meier-21

before you entered the educational credits, did TT say you OWED 1508 or were getting a refund of 1508? your question isn't clear on that item. 

and how much are your federal tax withholdings on your W-2s?  that could have something to do with it also. 

Did either of you receive any 1099-MISC documents?