When looking to decide which end of the point-spread you want to wager on, you should consider the ATS (against-the-spread record) of teams in the particular game situation.
For example, both teams may have similar spread records, but one team may excel (or more likely be undervalued) on the road, posting a stronger road ATS mark, while the opposing home team may be really poor (or similarly often overvalued) as a favorite at home.
Casual gamblers may overlook these factors seeing that the teams have similar ATS records and the home team usually wins the matchup.
Often it is that extra point or two that is getting backers of the team with the better spread record to the window.
We can also compare the situation to betting on totals, as well, as some teams may achieve OVER/UNDER results that are skewed towards one side of the betting total more frequently than the other.
Once again, don’t just compare the overall O/U record of the team, but break it down by home and away games, as well.