## Bayesian Draft Analysis Tool

This tool is intended to help decision-makers better assess the NFL draft market. Specifically, it estimates the probability each prospect will be available at each pick number.  The estimates are based on a Bayesian inference model based on consensus player rankings and projections from individual experts with a history of accuracy.

For details on how the model works, please refer to these write-ups:

- A full description of the purpose and capabilities of the model
- A discussion of the theoretical basis of Bayesian inference as applied to draft modeling
- More details on the specific methodology

If you want to jump straight to the results, here they are. But I recommend reading a little further for a brief description of what you'll find.

The interface consists of a list of prospects and two primary charts. Selecting a prospect displays the probabilities of when he'll likely be taken. You can filter the selection list by overall ranking or position.

The top chart plots the probabilities the selected prospect will be taken at each pick #. I think this chart is pretty cool because it illustrates the Bayesian inference process. You can actually see the model 'learn' as it refines its estimates with the addition of each new projection. Where there is a firm consensus among experts, the probability distribution is tall and narrow, indicating high confidence. When there is disagreement, the distribution is low and wide, indicating low confidence.

The lower chart is the bottom line. It's the take-away. It depicts the cumulative probability that the selected prospect will remain available at each pick #. For example, currently there's an 82% chance safety HaHa Clinton-Nix is available at the #8 pick but only a 26% chance he's available at #14. A team with an eye on a specific player could use this information in deciding whether to trade up or down, and in understanding how far they'd need to trade.

Hovering your cursor over one of the bars on the chart provides some additional context, including which team has that pick and that team's primary needs (according to nfl.com).

The box in the upper right gives you the player's vitals - school, position, height, weight. The expert projections used as inputs to the model are also listed. Currently those include Kiper (ESPN), McShay (Scouts, Inc.), Pat Kirwan(CBS Sports), Daniel Jeremiah (former team scout, NFL Network), and Bucky Brooks (NFL Network). Experts were selected for their  reputation, historical accuracy, and independence--that is, they don't all parrot the same projections. Not every prospect has a projection from each expert.

### 4 Responses to “Bayesian Draft Analysis Tool”

1. Reilly Pinkelnwert says:

This should be a fun tool to use while watching the draft this year. Well done! I'll be very interested in seeing how things turn out.

2. Kevin Kelley says:

Good stuff. I hope Jerry and Stephen Jones have this handy this weekend.

3. Anonymous says:

Kevin Kelly- don't hold your breath on Stephen & Jerry using this tool for at least 5 years.

4. ERych says: