Over the years, Jason Garrett has been consistent in emphasizing fourth quarter performance, but the results have not met expectations so far this year. Improved fourth quarter play in 2015 could be the difference between making the playoffs and a top 15 draft pick.
When Jason Garrett was asked a few years back which stats the Cowboys pay the most attention to, he answered turnover differential and 'winning the fourth quarter,' because he believes they are the two stats most significantly correlated with winning in the NFL. Here's Garrett's exact quote from August, 2011.
There were a lot of games in the NFL that were within one score in the fourth quarter, and the teams that went to the playoffs won a lot of those games.