The NFL combine explained: what actually gets measured

Six seconds of television, replayed for a fortnight. A young man in a compression shirt runs in a straight line, a number appears on the screen, and a portion of the football internet reorganises its mock draft around it. That is the NFL combine as most people meet it, and it is close to the least consequential thing happening in Indianapolis that week.

The NFL combine explained honestly is a four-day medical convention with a track meet bolted onto the side. The examinations are the event. The interviews are the second event. The drills are the part that sells advertising, and the clubs treat them as a cross-check on work they finished months earlier.

None of this is secret. The camp has an owner, a written invitation procedure, a published participation bar and a documented medical programme, and once you know how the week is actually organised the annual argument about whether a slow forty ruined somebody's draft stock starts to look like an argument about the wrong thing entirely.

The NFL combine explained: whose event it actually is

The combine is not an NFL production. It is run by National Football Scouting, a scouting service owned by a group of clubs, and its proper name is the National Invitational Camp. Jeff Foster has been its president since 2005, working from an Indianapolis office with a staff small enough to fit round one table. The job is duller and harder than the broadcast implies: collect, standardise and distribute information on several hundred young men so that thirty-two competing organisations can all read it in the same format, in the same week, with nobody gaining an advantage from the plumbing.

Invitations are voted. Clubs submit names of draft-eligible players, a committee of professional evaluators works through them position group by position group, and every player who clears the required number of votes is invited. Roughly three hundred attend in a normal year, and the exact list is published before the camp opens; the 2026 edition invited 319.

That list is not meant to be a ranking, and it becomes one anyway. A player left off it has lost the only occasion on which he would have been measured, examined and interviewed under identical conditions to his competition. He can still be drafted, and plenty are, but every club evaluating him is doing so with a thinner file than it holds on the man ranked one place above him.

There is also a bar on entry that has nothing to do with football. A background check turning up a conviction for a felony, or for a misdemeanour involving violence, a weapon, domestic violence or a sexual offence, keeps a prospect out of every part of the camp. Dismissal by a university or by the NCAA can do the same. The consequence is not a punishment in any formal sense. It is an information penalty, and it lands on the player: clubs still draft players who were not permitted to attend, but they draft them knowing less.

• 319Prospects invited to the 2026 camp
• 45Formal interviews permitted per club
• 18Minutes allowed per formal interview
• 30Pre-draft visits permitted per club

Access, not talent, is the scarce resource in Indianapolis. Prospects living or studying within fifty miles of a club's facility do not count against its thirty pre-draft visits.

Why it exists at all, and how it ended up in Indiana

Before the camp existed, every club that wanted a prospect's medical file arranged its own examination, and every club that wanted him timed sent somebody to time him. The result was a scheduling farce: a well-regarded senior might be poked, prodded, X-rayed and sprinted by a dozen different organisations, each producing its own numbers by its own methods, none of which agreed.

National Football Scouting's answer, in 1982, was a single camp in Tampa. It drew 163 players. Rival scouting groups ran their own versions for the clubs that did not belong to NFS, so for three years the sport had the same fragmentation with fewer venues.

The camps merged in 1985, with every club in the league agreeing to use one event, and the combined camp shortly afterwards settled in Indianapolis. It started in the Hoosier Dome and now runs at Lucas Oil Stadium, and it has been held there ever since apart from a pandemic interruption. The city keeps it for reasons that are entirely practical and slightly comic: a domed stadium, a convention centre, a large hospital and a cluster of hotels, all joined by covered walkways, in a place where late February is cold enough that nobody wanders off.

1982, Tampa163

2026, Indianapolis319

The 1982 figure is the attendance at the first National Invitational Camp in Tampa. The 2026 figure is the published invitation list for Indianapolis.

Show the numbers

The camp then and now, by players invited

Item	Players
1982, Tampa	163
2026, Indianapolis	319

The growth is not really about the number. It is about what the number bought. Once every club agreed to accept one set of measurements, the measurements became a standard, and a standard is worth more than the data in it. Two clubs arguing about a prospect are now arguing about the same file.

The NFL combine explained through one prospect's week

A prospect does not spend four days running drills. He spends most of a week being processed, and the running happens near the end of it, when he is tired.

1. 1Registration and measurementHeight, weight, arm length, hand size and wingspan are taken and recorded. Every figure a college programme had been rounding upwards is corrected here, permanently.
2. 2Medical examinationsOrthopaedic and internal examinations, imaging, blood work, cardiac screening and baseline concussion testing. The largest single block of time in the week and the one that moves players furthest.
3. 3Cognitive and psychological testingAssessments aimed at processing speed and decision-making, administered to everybody, with results going to clubs rather than to the public.
4. 4Media session and club interviewsA short press availability, then the formal interviews, each capped at eighteen minutes, with a hard limit on how many prospects a club may see.
5. 5On-field testingThe timed and measured drills, then the position-specific work, run in a scripted order in front of every club's coaching and scouting staff at once.

The order is set by the scouting service and shifts slightly by position group. The televised portion is the last step.

Two things about that order matter. The medicals come first because they are the reason the event exists, and because a player who fails one has just changed his own week: he will be told what a club's doctor found, and he may decide not to work out at all. The on-field testing comes last, after days of standing about, poor sleep and a hotel diet, which is one small reason combine times and pro day times differ.

The medicals are the event, and almost nobody reports them

Every prospect at the camp goes through two distinct examinations. The internal side is a physician's assessment: cardiovascular screening, blood work, an electrocardiogram, kidney, liver and pulmonary function. The orthopaedic side is a survey of everything that has ever been injured, with imaging ordered on the spot for anything that looks unresolved. Baseline neurocognitive testing is taken so that a future concussion has something to be compared against.

The volume is the part that surprises people. In one documented year the camp produced 365 MRI scans on 333 players inside four days. That is a hospital running at capacity for the better part of a week on a single cohort of twenty-two-year-olds, most of whom feel perfectly well.

All of it goes into an electronic medical record that every club can read. This is the quiet genius of the arrangement and the thing that makes the camp irreplaceable. A club's doctor is not relying on a summary from a college trainer or on what an agent chose to disclose. He has images, notes and history in a shared system, and if a player is recalled for further testing the file is updated for everybody at once.

The recall is a real stage of the process. Each spring the scouting service brings a group of players back, usually around fifty, for a medical-only session: the ones who were mid-rehabilitation in February, or whose imaging showed something that needed watching, or who have had surgery since. They go to an Indianapolis hospital for fresh scans, then cycle through a series of rooms where small groups of club doctors examine one specific joint each and ask about the rehabilitation. It moves fast, because each examination has exactly one question to answer.

A medical grade can move a player further than any workout, and it moves him invisibly. Nobody publishes it. When a prospect slides on draft night and the broadcast cannot explain why, the explanation is very often sitting in that shared record, and the people who know it have no reason to say so. This is also why coverage of the selection meeting itself so regularly describes a pick as a surprise when it surprised nobody in a draft room.

Forty-five names, eighteen minutes each

The interview allowance is the tightest constraint of the week and the one clubs argue about hardest. Each club may conduct forty-five formal interviews, of eighteen minutes apiece. That is thirteen and a half hours of face-to-face time, spread across a field of three hundred, and the choosing of the forty-five is itself a strategic act.

It used to be sixty interviews of fifteen minutes. The trade, made when the on-field workouts were pushed into the evening for television, swapped a quarter of the club's meetings for three extra minutes in each of the ones that survived. Total contact time fell. Clubs did not love it, and the reason they accepted it is the reason most scheduling in professional sport goes the way it goes.

Eighteen minutes is not long enough for anything except a test. So clubs test. A quarterback gets a whiteboard and a play he has never seen, drawn in terminology he does not use, and is asked to install it and then defend it against a look. An offensive lineman gets a protection call and a blitz. A defensive back gets a coverage rule and a formation that breaks it. What the club is measuring is not whether the answer is right. It is how the player behaves in the ninety seconds after he realises he does not know.

The other half of the room is background. Every club has read the same reports, and the interview is where a prospect is asked directly about the thing in his file. Some clubs have historically done this badly enough to generate news stories of their own. Most do it because the alternative is committing several million dollars of guaranteed money to a person they have never spoken to.

There is a separate, informal circuit of conversations in hotel lobbies and corridors all week, and none of that is capped. The formal forty-five is the part with a stopwatch on it.

The measurements are thresholds, not trivia

Height, weight, arm length, hand size and wingspan get read out like the back of a trading card and treated as filler. At several positions they are closer to gates.

The reason is geometry rather than fashion. An offensive tackle's job is to reach a defender who is trying to run around him, and reach is a physical quantity: arm length sets how early he can make contact and how long he can keep a pass rusher from folding him backwards. Clubs carry positional minimums, informal but real, and a tackle who measures under one gets moved inside on somebody's board before he has done a single drill. A cornerback's wingspan changes the size of the catch window he can contest. Hand size on a quarterback matters less than it is said to and is not nothing, because it interacts with ball security in bad weather.

The other function is correction. College programmes list players at heights and weights chosen for the recruiting brochure. The camp establishes what the player is, in stocking feet, on a certified scale, in front of everybody. That is a small, unglamorous public service, and it is the reason a prospect can lose two inches on a Tuesday morning without anybody having done anything to him.

Body scanning arrived at the camp in 2023, initially alongside the manual system rather than in place of it. The direction of travel is obvious: a scan gives limb lengths, segment proportions and body composition in one pass, which is both more information and less of somebody standing on a box with a tape measure.

The drills, and what each of them is actually asking

Seven tests make up the standard menu, and each exists to isolate something the tape shows only in combination with everything else.

The 40-yard dash is timed at 10 and 20 yards as well as at the end. Most positions never run forty yards in a straight line, and the splits are what the clubs use: the ten-yard split is close to a pure measure of initial acceleration, which is what an interior lineman or an edge rusher actually needs from his legs. The full forty matters for the positions that genuinely run away from people.

The bench press is 225 pounds, repeated to failure. It is not a maximum strength test and was never meant to be one. It measures repeatable upper-body endurance against a fixed load, which is why it separates linemen usefully and says close to nothing about a wide receiver.

The vertical jump and the broad jump both measure explosive power, one upwards and one forwards, and they have the best claim of anything on the list to be measuring an underlying physical quality rather than a learned skill. They are also the hardest to fake and the cheapest to run.

The three-cone drill and the 20-yard shuttle are change-of-direction tests. The shuttle, five yards one way, ten back, five to finish, measures lateral acceleration and the ability to stop and reverse. The three-cone adds a turn around a corner under load. Both reward short, compact athletes and punish long ones, which is why a defensive end's three-cone time is read against a different scale from a slot receiver's.

The 60-yard shuttle is the closest thing on the list to a conditioning test, and the least attended.

Then come the position drills, scripted by the scouting service and run by coaches, and these are worth more than the timed work for one reason: they are the only part of the week where a prospect performs a football movement rather than an athletic one. A receiver running a route from a stationary start against nobody is not football. A receiver adjusting his body to a badly thrown ball is at least adjacent to it.

The 40 time on your screen is not the 40 time the club is using

A combine forty is a hybrid measurement, and understanding why explains most of the confusion around the number.

The runner starts himself. There is no gun, no reaction, no signal to respond to, which means there is nothing for a machine to trigger on. So the clock is started by a human being watching for first movement, and stopped electronically by a laser at the finish. That method has been the standard since the late 1990s.

It sits between two other methods. A fully hand-held time, started and stopped by a person, is faster, because human reaction lag at the start is worth more than it costs at the finish; published estimates of the gap between hand and electronic timing run from about fifteen hundredths of a second to nearly a quarter of a second. A fully automatic time, laser at both ends, is slower than either. The league experimented with fully automatic timing at the camp in 2012 and the numbers were never released, for the entirely human reason that they would have made every player look worse than the figures everyone had grown up quoting.

Lower end of the reported range0.15s

Upper end of the reported range0.24s

The range reported in the sprint testing literature for the same run measured both ways. The combine's method sits between them, with a hand start and an electronic finish.

Show the numbers

The published gap between hand timing and electronic timing

Item	Seconds faster when hand timed
Lower end of the reported range	0.15s
Upper end of the reported range	0.24s

The practical consequence arrives every March, when pro days start producing times that beat the combine. A pro day is run on the player's own campus, on his own surface, by people who want him to do well, often with a hand-held watch. A tenth of a second is inside the measurement error between those two environments, which is why a scout will quietly discount a campus time and why a genuinely quick pro day number changes almost nothing.

The cognitive test changed. The argument did not.

For decades every prospect sat a general aptitude test with fifty questions and twelve minutes, and every year a few scores leaked and were laughed at. It was dropped ahead of the 2022 camp, having survived long past the point at which anyone could explain what a vocabulary question had to do with reading a safety rotation.

What replaced it measures processing rather than knowledge: perception speed, visual search, how quickly a player predicts where a moving object is going, impulse control, the ability to improvise once the first read is gone. That is at least aimed at the right target. A quarterback's job is a series of decisions taken in under three seconds on incomplete information, and if anything off the field is going to correlate with that, a speeded visual task is a better candidate than an analogies test.

Whether it works is a separate question, and the clubs are not publishing their answer. Scores leak anyway, and the leaks are worse than useless, because a percentile with no context and no error bar attached to a twenty-one-year-old gets read as a verdict. The test's own developers have publicly asked people to stop treating it that way.

What the research actually found, and what it did not

The best-known peer-reviewed test of the camp's predictive value was published in 2008 in the Journal of Strength and Conditioning Research by Frank Kuzmits and Arthur Adams. They took quarterbacks, running backs and wide receivers drafted between 1999 and 2004, correlated their combine results against their professional production, and found no consistent statistical relationship. The one exception was the sprint tests for running backs.

That finding gets quoted as proof the combine is theatre. It is not, and the reason is a piece of statistics worth carrying around, because the same trap is everywhere in sport.

The sample is only players who were drafted. Everyone who tested badly enough to be filtered out beforehand is missing from it, which means the study is measuring whether small differences matter among people who have already cleared the bar. Restricting the range like that pushes correlations towards zero almost mechanically. It is the same reason height barely predicts anything among professional basketball players while predicting a great deal in the general population.

So the honest reading is narrower and more useful than the headline. The evidence does not support ranking prospects by their testing numbers. It says nothing at all about whether the testing works as a filter, which is how clubs actually use it. Knowing that a prospect is an extreme outlier, fast or slow, heavy-footed or unusually explosive, is information. Knowing he ran four hundredths quicker than the next man is noise, and a club that treats it as signal has invented a difference the measurement is not precise enough to see.

Relative Athletic Score, and the right way to read a composite

The public's best tool for reading the testing arrived from outside the industry. Kent Lee Platte built Relative Athletic Score in 2013: take a prospect's height, weight and testing results, compare every one of them against the historical record for his position stretching back to the late 1980s, and express the composite on a nought to ten scale.

The design decision that makes it work is the positional comparison. A 4.6-second forty is unremarkable for a receiver and remarkable for a defensive tackle, and any composite that ignores that is measuring body type rather than athleticism.

Two cautions come with it. The first is that the score is a percentile, not a grade. A number near ten means the workout was historically unusual for that position; it does not mean the player is good, and the archive is full of exceptional workouts attached to unexceptional careers. The second is a coverage problem. A full score needs height, weight, the forty with both splits, the bench, both jumps, the short shuttle and the three-cone, so a prospect who ran three drills and skipped the rest often has no score at all. Absence from the table is not weakness. It is frequently the opposite: a highly rated player declining to sit a test he cannot win.

• 10Measurement and testing inputs required
• 10Top of the scale
• 1987Compared against everyone at the position since
• 0Cost to look one up

A positional percentile expressed on a ten-point scale. Built by Kent Lee Platte in 2013 from the historical testing archive.

Why so many prospects now skip so much of it

Attendance at individual drills has been falling for years, and the reasons stack.

The scheduling change that moved the workouts into the evening also moved the bench press onto the same day as everything else. A prospect now has to decide whether pressing 225 pounds to failure is worth the arms he will have an hour later in the position drills. Plenty conclude it is not.

Underneath that sits the economics. A well-regarded prospect arriving in Indianapolis has a range of outcomes with a floor under it. He can raise the ceiling a little with a good workout and lower the floor a lot with a bad one, and his agent can do that arithmetic in his sleep. So he takes the medicals, sits the interviews, submits to the measurements, declines the tests he is not confident in, and reschedules them for a campus pro day with a friendly clock. The rational move for the individual makes the shared standard slightly worse for everyone, which is the ordinary shape of a collective action problem.

Then there is preparation. Prospects now spend the weeks after their final college game at specialist facilities being coached specifically in the seven tests. Starting technique in the forty, the arm swing on a broad jump, the footwork around the three-cone: all of it is trainable, and all of it is trained. The tests still measure something real, but part of what they measure is who spent eight weeks and a five-figure sum learning how to take them.

The college calendar has moved too. With a longer postseason on the college side and a transfer market that reshuffles rosters every year, the tape a scouting department graded and the athlete standing on the scales in February can be separated by a good deal more than they once were.

What happens after Indianapolis

The camp does not end the evaluation. It restocks it.

Pro days follow through March, on campus, and their real value is not the times. It is access to players who were never invited, a second look at anyone who was injured in February, and position work the camp's standard script does not cover. A club's area scout has a relationship with that programme and will get an hour with people the television cameras never see.

Then the visits. Each club may bring thirty non-local prospects to its own facility, with anybody living or studying within fifty miles of it exempt from the count, which quietly hands clubs in football-dense regions more looks for free. Thirty is a small number against a draftable pool in the hundreds, so spending one is a decision rather than a routine. Those visits get used for medical rechecks with the club's own specialists, for long interviews without an eighteen-minute clock, and for the sort of background work nobody discusses in public.

All of it feeds a board, and the board is the only artefact that matters. What a club builds between February and April is a ranked list with medical flags, character notes and scheme fits attached, and the price it will pay to move up or down that list is set by where a player sits on it, not by what he ran. The whole apparatus exists to make one list slightly better than thirty-one others. The same logic governs what happens next, because a drafted player arrives on a contract whose price was fixed before anyone knew whether he was any good, and a cheap mistake is survivable in a way an expensive one is not.

How to watch the camp and actually learn something

If you want the week to be informative rather than merely entertaining, four habits do most of the work.

Read the measurements before the times. Arm length on a tackle, weight on a defensive lineman who was listed twenty pounds heavier, the difference between a programme's listed height and a real one. These are facts, they are new, and unlike a forty time they cannot be trained for in eight weeks.

Treat the testing as a filter with wide error bars. Note the outliers at both ends and ignore the middle. If two prospects are separated by three hundredths of a second, the correct conclusion is that the test could not tell them apart.

Watch who is not testing, and ask why. A first-round prospect skipping the bench press is managing risk. A projected late-rounder skipping everything has usually been told something by a doctor.

Wait for the recall list. The names brought back for the April medical session are the closest thing to a public signal that clubs have a question about somebody's body, and it arrives weeks before anyone has to act on it.

None of that will tell you who a club is going to take. It will tell you what the club has just learned, which is the more interesting question and the one the broadcast is structurally incapable of answering, because the interesting parts of the week happen in examination rooms and hotel suites with the door shut.

More on how the rest of the machine fits together, from the wage scale that prices these players to the trade market that moves them, is collected in the American football archive.