Take a look at these numbers: plus-114, plus-21, plus-18, minus-14. Those are USC’s scoring differentials by quarter for the 2014 season.

It’s pretty easy to detect a pattern: The Trojans were a dominant team in the first quarter, decent in the second and third, below average in the fourth. As games progressed, they gradually got worse.

The hard part to figure out is why.

It was the one question USC coach Steve Sarkisian struggled to answer. But he knows it’s an area where the Trojans must improve.

“If we want to be a championship-caliber football team, we have to be better in the fourth quarter,” Sarkisian said the day after USC’s season-ending victory over Nebraska in the Holiday Bowl.

“We have to be better offensively in our ability to score points, and we have to better defensively in getting those critical stops at the most critical moments. That will be a huge focus of ours throughout this entire offseason. And it won’t just be physical. It won’t just be emotional. It will be also tactical, because it is a huge component to really successful teams.”

The examination should begin with a look in the mirror.

In the five games in which they squandered or almost squandered second-half leads – Arizona State, Arizona, Utah, Cal and Nebraska – the Trojans were not as aggressive in the second half as they were in the first.

In all five of those games, USC passed the ball more than it ran in the first half and ran more than it passed in the second. The totals are somewhat startling:

First halves: 119 passes, 84 runs

Second halves: 70 passes, 111 runs

USC led every one of those games at halftime, and there’s a natural tendency to run more when protecting a lead. But there’s also something to be said for sticking with what’s working. And for playing to win as opposed to playing not to lose.

The defense played a role as well. My Twitter feed and e-mail inbox were filled every Saturday night/Sunday morning with complaints about coordinator Justin Wilcox’s conservative schemes.

Colleague Ryan Abraham of USCFootball.com reported in mid-November that USC had blitzed less than any Power Five team in the country at that point in the season. I believe the fourth-quarter collapse against Arizona State spooked the coaching staff.

Before the Hail Mary everyone remembers, Kevon Seymour got burned in one-on-one coverage without safety help. The following week, USC nearly allowed Arizona to dink-and-dunk its way to a comeback victory. (Arizona’s 43 completions were a record for a USC opponent, topped three weeks later by Washington State.) Take a look at the first-half/second-half pass-defense splits for the Cal and Nebraska games:

First half: 256 yards, 53.8 completion pct.

Second half: 404 yards, 66.0 completion pct.

USC’s youth in the secondary factored into its generally conservative approach, as Sarkisian acknowledged during the season. In his season-ending teleconference, he pushed for better man-to-man coverage in critical situations, perhaps a sign of a more aggressive approach next fall.

The Trojans also will have more scholarship players next season with the sanctions finally lifted, and that should help as well. Although Sarkisian never would admit it, it’s reasonable to assume that USC’s low numbers contributed to its fourth-quarter issues, which mostly occurred in the latter part of the season.

I don’t think it’s entirely a coaching issue. Here’s another string of numbers: minus-48, plus-8, plus-125. Those are Washington’s second-half scoring differentials in Sarkisian’s final three seasons in Seattle. The Huskies were a terrific third-quarter team in 2013 – plus-119 – suggesting that adjustments were made. And providing hope that some are coming.