Without examining your return (we can't see it in this
public forum), it's impossible to say exactly what caused your refund to
decrease. However, there's a high probability that at least one reason is
listed in the FAQ below. I recommend printing your 2016 and 2017 returns and
comparing them line by line to see what changed.
https://ttlc.intuit.com/replies/3301788
See this FAQ for how to print
after filing:
https://ttlc.intuit.com/replies/4193463
