Why Market Freshness Matters

A sportsbook line is the price a book is offering at one moment. Between the first offer and kickoff it can move many times as books take positions, as news arrives and as other books adjust. A line recorded on Tuesday and a line recorded two hours before kickoff are two different observations of a market that kept moving in between.

So a line without a time is incomplete. FDI records when each quote was observed and shows that time next to the figure. Two numbers taken at different moments are never presented as if they described the same market.

Why the timestamp matters in the model vs market guide

• Injury and availability news, which can change a player’s expected role in minutes.
• Weather that firms up closer to the game.
• Books adjusting to one another, so a line that was an outlier drifts back toward the pack.
• The simple passage of time: early lines are often posted with wider uncertainty and tighten later.

None of that is visible in an old quote. If a line was captured before the news that moved it, anything calculated from it inherits that blind spot.

FDI treats a quote as current only within a fixed window after it was captured, and the rule is the same for every game. Once a quote falls outside that window it is marked as not current. The line is still shown, with its capture time and a clear “not current” label, because knowing where the market stood is still useful context.

What changes is what FDI will calculate from it. On the Player Props board and dossier, against a line that is not current, FDI shows no projection-minus-line difference and no model probability. As an illustration, a projection of 5.8 beside a stale line of 5.5 does not produce a “+0.3”. The difference would describe a market that may no longer exist.

• Current line for the same player → difference shown (projection minus line), and a model probability if the line matches a modeled threshold exactly.
• Line not current → line and capture time shown, marked not current; no difference and no probability.
• No line at all → the projection stays visible and the market cell says there is no current line; the player is not hidden and is not marked as out.

See current and not-current markets in the sample

FDI freezes its player projections two hours before kickoff. That timing is deliberate — the record has to exist before the game — but it means the projection cannot see anything that happens after it. The market can.

The clearest example is the inactive list. NFL teams announce which players will not dress 90 minutes before kickoff, about half an hour after FDI’s projections are frozen. If a teammate is ruled inactive, a player’s expected role can change, and books can adjust their lines within minutes. The frozen projection stays exactly as it was, by design.

• A line observed after the inactive list may reflect information the frozen projection does not have.
• A line observed well before it may be the one that is missing information.
• Either way, the capture time is what tells a reader which situation they are looking at.

This is one reason FDI shows the observation time beside every quote rather than a bare number, and why a difference between a projection and a line is only ever a starting point.

Books do not quote every player in every game. A missing line can mean the market simply was not offered for that player, that it was pulled for a while, or that the capture did not include it. It does not, on its own, mean the player is out.

FDI therefore keeps the projection and the market as separate states. A projection with no current line still appears, labelled “No current line.” It is not converted into a missing read, and it is not treated as evidence about availability.

It would be easy to compute a difference against the last line seen and show it without comment. The number would look exact, and a reader would have no way to know it described an old market. Refusing to show it is less convenient, but it keeps every comparison on the page anchored to a market that actually existed when the page says it did.

The same principle runs through the rest of FDI: model outputs are frozen before kickoff and never revised, and when the information is not there a view says so instead of filling the space.

How prospective tracking keeps the order of events