Says FiveThirtyEight.com:

Andy Reid is one of just six coaches who have led the same team since 2013, an elite cadre of coaches who have earned their longevity by winning.

Of that group, Reid ranks third in fourth-down aggressiveness in the regular season (26.6 percent), with Baltimore Ravens head coach John Harbaugh pacing the field with a 43.4 percent go-for-it rate.

But when the playoffs hit, Reid appears to transform into a hyper-aggressive wild man.

Since becoming coach of the Chiefs, Reid has attempted to convert to a new set of downs in eight of his 14 playoff opportunities — more than double his regular-season rate.2

Regular vs. postseason go-for-it rates since 2013 for the six longest-tenured NFL head coaches

REGULAR SEASONPOSTSEASON
COACHTEAMOPPSWENTGO RATEOPPSWENTGO RATEDIFF
Andy ReidKC1393726.6%14857.1%+30.5%
John HarbaughBAL994343.414642.9-0.6
Pete CarrollSEA1823921.426519.2-2.2
Mike TomlinPIT1542918.813215.4-3.4
Sean PaytonNO1544629.914321.4-8.4
Bill BelichickNE1884825.537513.5-12.0

Through the 2020 divisional round.

Go-for-it opportunities are those in which the model believes there is a win probability edge to be gained of at least 0.5 percentage points by going for it on fourth down. Plays on which win probability was below 20 percent were removed on the assumption that they were desperation calls.

https://fivethirtyeight.com/features/some-coaches-shy-away-from-risk-in-the-playoffs-not-andy-reid/?ex_cid=538email