Get started with nflseedR

Preface

nflseedR essentially performs two tasks:

Calculation of NFL standings with nfl_standings() based on game results of one or more seasons, especially taking into account the comprehensive and sometimes complicated tie-breaking procedures for division ranks, conference seeds and the draft order. Read this article for further information on the implemented tie-breakers.
Running thousands of simulations (Monte Carlo style) of an NFL season with nfl_simulations(). The standings from point 1 and especially the conference seeds are needed to determine playoff participants. Basically, the first point only exists because we need it to carry out the simulations.

The actual core of a simulation is the generation of game results based on any information that the user deems important. This is why nflseedR is virtually extensible. By default, a simple ELO model is implemented that works with initial starting ELO values and updates them from week to week based on game results. However, the user can write their own function for calculating game results and pass it to nflseedR together with any additional data that may be required.

Usage

Standings

We need real or simulated match data to determine standings. The required variables are specified in the documentation of the function nfl_standings().

Here are games data from the 2023 and 2024 seasons.

games <- nflreadr::load_schedules(2023:2024)

We can pass this data directly to nflseedR and calculate standings. It defaults to compute division ranks as well as conference ranks for all teams and it applies tiebreakers through strength of schedule.

standings <- nflseedR::nfl_standings(games, ranks = "DRAFT")
#> ℹ 20:32:10 | Initiate Standings & Tiebreaking Data
#> ℹ 20:32:10 | Compute Division Ranks
#> ℹ 20:32:11 | Compute Conference Ranks
#> ℹ 20:32:11 | Compute Draft Order
# Let's view the structure of the output
str(standings, max.level = 1, width = 50, strict.width = "cut")
#> Classes 'data.table' and 'data.frame':   64 obs. of  24 variables:
#>  $ season             : int  2023 2023 2023 2023..
#>  $ team               : chr  "BUF" "MIA" "NYJ" "..
#>  $ conf               : chr  "AFC" "AFC" "AFC" "..
#>  $ division           : chr  "AFC East" "AFC Ea"..
#>  $ games              : int  17 17 17 17 17 17 1..
#>  $ wins               : num  11 11 7 4 13 11 10 ..
#>  $ true_wins          : int  11 11 7 4 13 11 10 ..
#>  $ losses             : int  6 6 10 13 4 6 7 8 7..
#>  $ ties               : int  0 0 0 0 0 0 0 0 0 0..
#>  $ pf                 : int  451 496 268 236 483..
#>  $ pa                 : int  311 391 355 366 280..
#>  $ pd                 : int  140 105 -87 -130 20..
#>  $ win_pct            : num  0.647 0.647 0.412 0..
#>  $ div_pct            : num  0.667 0.667 0.333 0..
#>  $ conf_pct           : num  0.583 0.583 0.333 0..
#>  $ sov                : num  0.471 0.358 0.454 0..
#>  $ sos                : num  0.471 0.45 0.502 0...
#>  $ div_rank           : int  1 2 3 4 1 2 3 4 1 2..
#>  $ div_tie_broken_by  : chr  "Head-To-Head Win "..
#>  $ conf_rank          : int  2 6 13 16 1 5 7 8 4..
#>  $ conf_tie_broken_by : chr  "Head-To-Head Swee"..
#>  $ exit               : chr  "DIV" "WC" "REG" ""..
#>  $ draft_rank         : int  28 21 10 3 30 23 20..
#>  $ draft_tie_broken_by: chr  NA NA NA NA ...
#>  - attr(*, ".internal.selfref")=<externalptr>

nflseedR also provides functionality to create a “pretty” html table using the gt package. Use nfl_standings_prettify() with the output of nfl_standings() to create the table. It allows grouping by division, conference or overall and it can sort by division rank, conference rank (seed), and draft rank.

The default groups by division and sorts by division rank.

# It doesn't allow more than one season
s <- standings[season == 2024]
nflseedR::nfl_standings_prettify(s)

Div Rank	G	W	L	T	pf	pa	pd	pct	Div PCT	Conf PCT	sov	sos	exit	Division Tie broken by	Conf Rank	Conference Tie broken by	Draft Rank	Draft Tie broken by
2024 NFL Standings
AFC East
1	17	13	4	0	525	368	157	0.765	0.833	0.750	0.448	0.467	CON	—	2	—	30	—
2	17	8	9	0	345	364	-19	0.471	0.500	0.500	0.294	0.419	REG	—	10	—	13	—
3	17	5	12	0	338	404	-66	0.294	0.333	0.417	0.341	0.495	REG	—	11	—	7	—
4	17	4	13	0	289	417	-128	0.235	0.333	0.250	0.471	0.471	REG	—	13	SOV (2)	4	—
AFC North
1	17	12	5	0	518	361	157	0.706	0.667	0.667	0.525	0.529	DIV	—	3	—	27	—
2	17	10	7	0	380	347	33	0.588	0.500	0.583	0.453	0.502	WC	—	6	Head-To-Head Sweep (2)	21	Conference Tiebreaker
3	17	9	8	0	472	434	38	0.529	0.500	0.500	0.314	0.478	REG	—	8	—	17	—
4	17	3	14	0	258	435	-177	0.176	0.333	0.250	0.510	0.536	REG	—	15	SOV (2)	2	—
AFC South
1	17	10	7	0	372	372	0	0.588	0.833	0.667	0.376	0.481	DIV	—	4	—	25	—
2	17	8	9	0	377	427	-50	0.471	0.500	0.583	0.309	0.457	REG	—	9	Head-To-Head Sweep (2)	14	—
3	17	4	13	0	320	435	-115	0.235	0.500	0.333	0.265	0.478	REG	—	12	Conference Win PCT (3)	5	—
4	17	3	14	0	311	460	-149	0.176	0.167	0.250	0.431	0.522	REG	—	16	—	1	—
AFC West
1	17	15	2	0	385	326	59	0.882	0.833	0.833	0.463	0.488	SB	—	1	—	31	—
2	17	11	6	0	402	301	101	0.647	0.667	0.667	0.348	0.467	WC	—	5	—	22	—
3	17	10	7	0	425	311	114	0.588	0.500	0.500	0.394	0.502	WC	—	7	—	20	Conference Tiebreaker
4	17	4	13	0	309	434	-125	0.235	0.000	0.250	0.353	0.540	REG	—	14	—	6	—
NFC East
1	17	14	3	0	463	303	160	0.824	0.833	0.750	0.424	0.453	SB_WIN	—	2	—	32	—
2	17	12	5	0	485	391	94	0.706	0.667	0.750	0.358	0.436	CON	—	6	—	29	—
3	17	7	10	0	350	468	-118	0.412	0.500	0.417	0.387	0.522	REG	—	11	—	12	—
4	17	3	14	0	273	415	-142	0.176	0.000	0.083	0.412	0.554	REG	—	16	—	3	—
NFC North
1	17	15	2	0	564	342	222	0.882	1.000	0.917	0.494	0.516	DIV	—	1	—	28	—
2	17	14	3	0	432	332	100	0.824	0.667	0.750	0.408	0.474	WC	—	5	—	24	—
3	17	11	6	0	460	338	122	0.647	0.167	0.500	0.412	0.533	WC	—	7	—	23	—
4	17	5	12	0	310	370	-60	0.294	0.167	0.250	0.388	0.554	REG	—	13	Head-To-Head Sweep (2)	10	—
NFC South
1	17	10	7	0	502	385	117	0.588	0.667	0.667	0.465	0.502	WC	—	3	Conference Win PCT (2)	19	Head-To-Head (2)
2	17	8	9	0	389	423	-34	0.471	0.667	0.583	0.426	0.519	REG	—	9	Conference Win PCT (2)	15	—
3	17	5	12	0	341	534	-193	0.294	0.333	0.333	0.329	0.498	REG	SOV (2)	14	Division Tiebreaker	8	—
4	17	5	12	0	338	398	-60	0.294	0.333	0.333	0.306	0.505	REG	SOV (2)	15	Division Tiebreaker	9	—
NFC West
1	17	10	7	0	367	386	-19	0.588	0.667	0.500	0.441	0.505	DIV	SOV (2)	4	—	26	—
2	17	10	7	0	375	368	7	0.588	0.667	0.500	0.424	0.498	REG	SOV (2)	8	—	18	—
3	17	8	9	0	400	379	21	0.471	0.500	0.333	0.404	0.536	REG	—	10	—	16	—
4	17	6	11	0	389	436	-47	0.353	0.167	0.333	0.402	0.564	REG	—	12	—	11	—
nflseedR

But we can also do things like ordering the complete league by draft rank.

nflseedR::nfl_standings_prettify(s, grp_by = "nfl", order_by = "draft_rank")

Draft Rank	G	W	L	T	pf	pa	pd	pct	Div PCT	Conf PCT	sov	sos	exit	Div Rank	Division Tie broken by	Conf Rank	Conference Tie broken by	Draft Tie broken by
2024 NFL Standings
1	17	3	14	0	311	460	-149	0.176	0.167	0.250	0.431	0.522	REG	4	—	16	—	—
2	17	3	14	0	258	435	-177	0.176	0.333	0.250	0.510	0.536	REG	4	—	15	SOV (2)	—
3	17	3	14	0	273	415	-142	0.176	0.000	0.083	0.412	0.554	REG	4	—	16	—	—
4	17	4	13	0	289	417	-128	0.235	0.333	0.250	0.471	0.471	REG	4	—	13	SOV (2)	—
5	17	4	13	0	320	435	-115	0.235	0.500	0.333	0.265	0.478	REG	3	—	12	Conference Win PCT (3)	—
6	17	4	13	0	309	434	-125	0.235	0.000	0.250	0.353	0.540	REG	4	—	14	—	—
7	17	5	12	0	338	404	-66	0.294	0.333	0.417	0.341	0.495	REG	3	—	11	—	—
8	17	5	12	0	341	534	-193	0.294	0.333	0.333	0.329	0.498	REG	3	SOV (2)	14	Division Tiebreaker	—
9	17	5	12	0	338	398	-60	0.294	0.333	0.333	0.306	0.505	REG	4	SOV (2)	15	Division Tiebreaker	—
10	17	5	12	0	310	370	-60	0.294	0.167	0.250	0.388	0.554	REG	4	—	13	Head-To-Head Sweep (2)	—
11	17	6	11	0	389	436	-47	0.353	0.167	0.333	0.402	0.564	REG	4	—	12	—	—
12	17	7	10	0	350	468	-118	0.412	0.500	0.417	0.387	0.522	REG	3	—	11	—	—
13	17	8	9	0	345	364	-19	0.471	0.500	0.500	0.294	0.419	REG	2	—	10	—	—
14	17	8	9	0	377	427	-50	0.471	0.500	0.583	0.309	0.457	REG	2	—	9	Head-To-Head Sweep (2)	—
15	17	8	9	0	389	423	-34	0.471	0.667	0.583	0.426	0.519	REG	2	—	9	Conference Win PCT (2)	—
16	17	8	9	0	400	379	21	0.471	0.500	0.333	0.404	0.536	REG	3	—	10	—	—
17	17	9	8	0	472	434	38	0.529	0.500	0.500	0.314	0.478	REG	3	—	8	—	—
18	17	10	7	0	375	368	7	0.588	0.667	0.500	0.424	0.498	REG	2	SOV (2)	8	—	—
19	17	10	7	0	502	385	117	0.588	0.667	0.667	0.465	0.502	WC	1	—	3	Conference Win PCT (2)	Head-To-Head (2)
20	17	10	7	0	425	311	114	0.588	0.500	0.500	0.394	0.502	WC	3	—	7	—	Conference Tiebreaker
21	17	10	7	0	380	347	33	0.588	0.500	0.583	0.453	0.502	WC	2	—	6	Head-To-Head Sweep (2)	Conference Tiebreaker
22	17	11	6	0	402	301	101	0.647	0.667	0.667	0.348	0.467	WC	2	—	5	—	—
23	17	11	6	0	460	338	122	0.647	0.167	0.500	0.412	0.533	WC	3	—	7	—	—
24	17	14	3	0	432	332	100	0.824	0.667	0.750	0.408	0.474	WC	2	—	5	—	—
25	17	10	7	0	372	372	0	0.588	0.833	0.667	0.376	0.481	DIV	1	—	4	—	—
26	17	10	7	0	367	386	-19	0.588	0.667	0.500	0.441	0.505	DIV	1	SOV (2)	4	—	—
27	17	12	5	0	518	361	157	0.706	0.667	0.667	0.525	0.529	DIV	1	—	3	—	—
28	17	15	2	0	564	342	222	0.882	1.000	0.917	0.494	0.516	DIV	1	—	1	—	—
29	17	12	5	0	485	391	94	0.706	0.667	0.750	0.358	0.436	CON	2	—	6	—	—
30	17	13	4	0	525	368	157	0.765	0.833	0.750	0.448	0.467	CON	1	—	2	—	—
31	17	15	2	0	385	326	59	0.882	0.833	0.833	0.463	0.488	SB	1	—	1	—	—
32	17	14	3	0	463	303	160	0.824	0.833	0.750	0.424	0.453	SB_WIN	1	—	2	—	—
nflseedR

Please note that nfl_standings_prettify() returns a gt::gt() table so you can change it according to your own preferences.

Simulations

With nflseedR 2.0, we have rethought and implemented the execution of simulations from scratch. Particular attention was paid to flexibility and performance. As the usage of the new function nfl_simulations() differs from the old function simulate_nfl(), we will keep both variants for the time being and maintain two separate articles explaining how to use them.

It is strongly recommended to switch to nfl_simulations() because it is far superior to the old implementation in practically every respect, especially in terms of performance.

Go to this article for a detailed explanation of how to use nfl_simulations()
Go to this article for a detailed explanation of how to use simulate_nfl()

Sebastian Carl and Lee Sharpe

Preface

Usage

Standings

Simulations