Voting for the annual Baseball Writers' Association of America awards is hardly easy. There is a lot of pressure when filling out your ballot because of the pedigree and history that are attached to the awards.
If there was an “easy” one of the four, it would probably be Manager of the Year.
When it comes down to Rookie of the Year, Cy Young and Most Valuable Player, there are so many statistics that can be used to compare and contrast the candidates. It sometimes comes down to which ones the voters value more, and that often changes (i.e. the emergence of sabermetric numbers over the last decade).
But for Manager of the Year, there is really only one stat that matters: Record. Then that is often balanced against a team’s expectations coming into the season and any hardships they had to endure (roster changes, injuries, prolonged slums, etc.).
Voters also take a team’s talent level into consideration. Dave Roberts may never win another Manager of the Year award because the Dodgers are always loaded with MVP, Cy Young and Rookie of the Year candidates with World Series-or-bust aspirations.