Pete Carroll always used to joke that he refused to divulge Taylor Mays’ 40-yard dash time because no one would believe him if he did.

I guess now we’ll never know the truth.

The answer was supposed to be finally revealed once and for all Tuesday at the NFL scouting combine in Indianapolis. It looked for a minute as though Mays had delivered that jaw-dropping moment when it was announced he had recorded a 4.24 second 40-yard dash, which would have tied the record mark set by Tennessee Titans running back Chris Johnson in 2008.

But that listing was unofficial. Mays true mark was announced as 4.43 seconds, leaving everyone in the Lucas Oil Stadium befuddled. Timing can vary by a few hundredths of a second depending on who’s holding the stopwatch. But how does someone’s speed vary by two-tenths of a second?

There was a certain disappointment that lingered once the more reasonable time was announced. If the 6-foot-3, 230-pound Mays had truly run a 4.24, he would have gone down in history as one of the best combine performers of all time. Now he only gets the benefit of being labeled as one of your run-of-the-mill elite physical specimens.

Mays’ mark was still the best among defensive backs, but it’s easy to see why he would be disappointed with the new mark. It’s the equivalent of getting a 101 on your test only to have your professor take it back and regrade it as an 89. Sure, there’s some estimation involved, but there’s no accounting for such a discrepancy.

Cameras superimposed Mays’ run against those of other speedy prospects, leading to the conclusion that the former USC safety had to have run faster than the official time with which he was credited. In all likelihood, it will be a great mystery until everyone forgets about it in roughly a week.

But “40-gate” reinforced an important point: The NFL Draft focuses more on a collection of perceptions than it does exact information.

From the outside, the NFL draft is a neurotic organizer’s dream. Everything has to be categorized, ranked and sorted. Teams and analysts ramble about what they claim to definitively know. If someone is picked too high or too low or above another player, there must be immediate, inherently justified outrage.

But the truth is that there is no true sorting system for the NFL draft. The lack of predictability is what makes the event, when stripped of its hype, so enjoyable.

Many of our perceptions are not entirely based on criteria that accurately predict the success of future NFL players. How else would you describe JaMarcus Russell’s ascension to No. 1 overall draft pick despite a litany of questions about his ability to lead a team and make good decisions? Oh right, you could account for it by mentioning that he was drafted by the Oakland Raiders.

But there are plenty of other examples. The Miami Dolphins drafted wide receiver Ted Ginn Jr., ninth overall despite the fact that he had the notable handicap of struggling to catch the ball, which ranks pretty highly on the things you would want from a player of his position.

Teams, fans and analysts develop perceptions of players that evolve throughout the draft process. Of course, teams get in trouble when their perceptions of a flawed but talented player begin to drift away from the facts.

When looking at a player with an obvious upside but significant problems, teams almost act like girls who think they can fix that troubled guy they like so much. He’ll change, they say, once I get a crack at him. And of course, they end up getting burned.

But no matter what the team’s objective, it’s clear those perceptions matter more than the raw data.

So what’s the perception that followed Mays after the draft? Well, it is probably that he is capable of moving extremely fast in one direction, especially for a player of his size ­— insightful analysis, right?

I limit the statement at that because there are still questions about Mays that concern teams. Tony Pauline of Sports Illustrated wrote that Mays “was in bad form” during defensive back drills and showed poor fundamentals. And fairly or unfairly, Mays is now battling the reputation that he’s a workout warrior who still needs polishing.

Mays will get another chance to change teams’ opinion of him when he performs at USC’s pro day at the end of the month. The comfortable setting should give him the opportunity to show off his skills in the best possible context.

At the very least, he should give us another 40 time to talk about.

“Tackling Dummy” runs Thursdays. To comment on this article, visit dailytrojan.com or e-mail Michael at middlehu@usc.edu.