It is tempting but silly to judge a baseball manager based on the results of a few games. There are always things happening that we, the proletariat, do not understand (players’ health, their mood, their addiction to a phone-based video game).
But, given enough data, it is possible to tell if the manager is “good” at his job.
Ned Yost has managed just more than 2,400 baseball games. Here’s a statistic that seems important about those 2,400 baseball games: he’s won 48% of them. This makes him third-worst of active managers who’ve managed at least two seasons’ worth of games.