Credit Where It's Due — Who Makes the Films Good

The Equation

One line per film, 2,973 of them, solved all at once

Rating = 67.6baseline + Directorbonus + Writerbonus + DoPbonus + Editorbonus + Composerbonus + Starstop 3 billed

Each person has one bonus per job, the same in every film they work on. The baseline, 67.6, is the average rating across the log.
The bonuses are chosen to fit every film at once. At the answer, each person's bonus is what's left on their films after all their co-workers' bonuses are taken out: bonus = Σ (rating − prediction without them) ÷ (films + λ)
λ = 12 works like giving everyone 12 imaginary average films, so one great film can't top a chart. The data chose that value (see How It Works).

"Alone" in the tables below is the same sum, but crediting the person with the whole film. The gap between Alone and Credit is the credit that moved to (or from) their co-workers.

2,973Films

14,151Credits Weighed

12λ (Scepticism)

14.3 vs. 15.1Avg. Miss on Unseen Films

Directors Who Add the Most

Points a film gains, on average, for having them · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Quentin Tarantino	10	92.3	+11.2	+5.8
2	David Fincher	12	84.1	+8.2	+5.7
3	Stanley Kubrick	9	90.1	+9.7	+5.7
4	Paul Thomas Anderson	10	90.3	+10.3	+5.6
5	Sidney Lumet	14	81.6	+7.5	+5.5
6	Martin Scorsese	16	88.8	+12.1	+5.5
7	Roman Polanski	5	86.4	+5.5	+4.6
8	Wes Anderson	11	85.2	+8.4	+4.5
9	James Cameron	13	77.7	+5.3	+4.2
10	Brad Bird	6	88.3	+6.9	+3.9
11	Werner Herzog	7	86	+6.8	+3.8
12	Francis Ford Coppola	9	83.8	+6.9	+3.4
13	Martin McDonagh	4	93.5	+6.5	+3.4
14	John McTiernan	5	80	+3.7	+3.3
15	Victor Sjöström	3	91.3	+4.7	+3.2

Directors Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Rod Lurie	6	40.7	−9	−5.2
2	Antoine Fuqua	6	42.3	−8.4	−5.1
3	Tim Story	3	23.7	−8.8	−4.9
4	Rupert Wyatt	4	37	−7.6	−4.6
5	Brad Furman	6	42.7	−8.3	−4.4
6	George Clooney	9	55.6	−5.2	−4.2
7	Kenneth Branagh	6	48.3	−6.4	−3.9
8	Peter Hyams	4	44.3	−5.8	−3.9

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Ethan Coen 20 films +8.7 → +1.5
Joel Coen 19 films +9.7 → +2.6
Martin Scorsese 16 films +12.1 → +5.5
Peter Jackson 9 films +8.5 → +2.8
Quentin Tarantino 10 films +11.2 → +5.8
Paul Thomas Anderson 10 films +10.3 → +5.6

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Tim Story 3 films −8.8 → −4.9
Brad Furman 6 films −8.3 → −4.4
Rod Lurie 6 films −9 → −5.2
Lana Wachowski 6 films −5.3 → −1.8
Antoine Fuqua 6 films −8.4 → −5.1
Lilly Wachowski 5 films −3.1 → +0.1

Writers Who Add the Most

Points a film gains, on average, for having them · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Quentin Tarantino	12	90.6	+11.5	+6.5
2	Paul Thomas Anderson	10	90.3	+10.3	+5.6
3	James Cameron	10	83.1	+7.1	+5.5
4	Stanley Kubrick	7	93.6	+9.6	+5.3
5	Andrew Stanton	9	88.4	+8.9	+5.1
6	Wes Anderson	11	85.2	+8.4	+4.5
7	Lawrence Kasdan	5	86.6	+5.6	+3.7
8	Jonathan Nolan	4	88	+5.1	+3.7
9	George Lucas	11	76.6	+4.3	+3.6
10	Richard Maibaum	13	77.7	+5.3	+3.5
11	Martin McDonagh	4	93.5	+6.5	+3.4
12	Michael Wilson	4	89	+5.4	+3.3
13	Victor Sjöström	3	91.3	+4.7	+3.2
14	George Miller	6	83.8	+5.4	+3.2
15	Oliver Stone	9	77.4	+4.2	+3.2

Writers Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Steven Zaillian	17	60.7	−4	−5.1
2	William Monahan	6	54.3	−4.4	−4.2
3	Lawrence Konner	4	39.5	−7	−4.1
4	Jack Thorne	4	41.3	−6.6	−4.1
5	Akiva Goldsman	8	54.3	−5.3	−3.5
6	David Koepp	18	62.4	−3.1	−3.4
7	Steven Knight	5	53	−4.3	−3.4
8	John Brancato	6	52.3	−5.1	−3.3

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Ethan Coen 23 films +8.1 → +1.5
Joel Coen 23 films +8.5 → +2
Fran Walsh 7 films +8 → +1.6
Peter Jackson 8 films +8.2 → +2.1
Philippa Boyens 8 films +7.3 → +1.7
Quentin Tarantino 12 films +11.5 → +6.5

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Terry Rossio 10 films −6.6 → −1.6
Ted Elliott 6 films −4.4 → −0.3
Christopher Markus 5 films −4.9 → −1.4
Stephen McFeely 5 films −4.9 → −1.4
Lana Wachowski 8 films −5.5 → −2
Lilly Wachowski 7 films −3.6 → −0.2

Cinematographers Who Add the Most

Points a film gains, on average, for having them · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Conrad L. Hall	7	84.6	+6.3	+5.2
2	Wally Pfister	9	83.2	+6.7	+4.6
3	Owen Roizman	7	79	+4.2	+3.7
4	Michael Seresin	7	81	+4.9	+3.5
5	Stefan Czapsky	4	84	+4.1	+3.5
6	Edward Lachman	8	78.3	+4.3	+3.4
7	Arthur Edeson	9	80.3	+5.5	+3.4
8	Douglas Slocombe	5	83.2	+4.6	+3.3
9	Julius Jaenzon	3	91.3	+4.7	+3.2
10	Shabier Kirchner	7	76.1	+3.2	+3.2
11	Robert D. Yeoman	15	79.1	+6.4	+3.2
12	Dean Cundey	14	73.1	+3	+3.1
13	Sam Levy	5	85.8	+5.4	+3.1
14	Andrew Lesnie	11	83.4	+7.5	+2.9
15	Rodrigo Prieto	7	82.3	+5.4	+2.9

Cinematographers Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Paul Sarossy	4	29.5	−9.5	−6.6
2	Remi Adefarasin	7	43.7	−8.8	−6.4
3	David Tattersall	9	51.7	−6.8	−5.4
4	Larry Blanford	4	34	−8.4	−5.2
5	John Schwartzman	11	51.6	−7.6	−5
6	William A. Fraker	7	54	−5	−4.9
7	George Richmond	10	54.3	−6	−4.6
8	Anthony Dod Mantle	7	49.4	−6.7	−4.6

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Roger Deakins 29 films +5.7 → +0.9
Andrew Lesnie 11 films +7.5 → +2.9
Robert Richardson 21 films +5.4 → +1.4
Tristan Oliver 6 films +5 → +1.3
Patrick Lin 4 films +5.7 → +2.3
Michael Ballhaus 14 films +3.6 → +0.3

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Philippe Rousselot 14 films −5.3 → −1.7
Kramer Morgenthau 7 films −5.7 → −2.4
Larry Blanford 4 films −8.4 → −5.2
Larry Fong 6 films −6.7 → −3.6
Dariusz Wolski 22 films −6.1 → −3.1
Paul Sarossy 4 films −9.5 → −6.6

Editors Who Add the Most

Points a film gains, on average, for having them · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Thelma Schoonmaker	15	89.7	+12.3	+5.6
2	Sally Menke	7	92.3	+9.1	+3.8
3	Richard Francis-Bruce	8	80.4	+5.1	+3.7
4	Sam O'Steen	9	78.4	+4.7	+3.7
5	Peter Zinner	4	91.5	+6	+3.4
6	George Tomasini	7	82.9	+5.6	+3.4
7	Arthur Schmidt	13	71.1	+1.8	+3.3
8	Jon Gregory	6	86.3	+6.2	+3.3
9	Dylan Tichenor	14	80.3	+6.8	+3.3
10	Owen Marks	4	83.8	+4	+3.2
11	Christopher Rouse	7	76.1	+3.2	+3
12	Gabriel Fleming	4	79.5	+3	+3
13	Steve James	3	94	+5.3	+2.9
14	Barry Alexander Brown	5	78.6	+3.2	+2.9
15	Dede Allen	7	80.4	+4.7	+2.9

Editors Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Null	105	62	−5	−5.8
2	Jon Poll	11	51.5	−7.7	−5.5
3	Chris Lebenzon	21	54.6	−8.3	−5.5
4	David Rosenbloom	14	54.1	−7.2	−4.6
5	William Hoy	13	55.6	−6.2	−4.5
6	Lisa Lassek	7	53.6	−5.2	−4.5
7	Scott Evans	3	27.3	−8.1	−4.5
8	Alan Edward Bell	4	38.8	−7.2	−4.3

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Joel Coen 16 films +8.7 → +1.4
Ethan Coen 15 films +8.9 → +2
Thelma Schoonmaker 15 films +12.3 → +5.6
Sally Menke 7 films +9.1 → +3.8
Dylan Tichenor 14 films +6.8 → +3.3
Jabez Olssen 5 films +3.4 → 0

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Jeffrey Ford 11 films −5.5 → −2
Scott Evans 3 films −8.1 → −4.5
Peter S. Elliot 5 films −6.7 → −3.3
Bruce Green 3 films −6.2 → −3.2
Jeff McEvoy 4 films −4.5 → −1.5
Roger Barton 6 films −7.1 → −4.2

Composers Who Add the Most

Points a film gains, on average, for having them · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Howard Shore	29	84.2	+11.8	+6.8
2	Marvin Hamlisch	5	86.8	+5.7	+4.1
3	Michael Brook	5	84.2	+4.9	+4.1
4	Michael Giacchino	32	73.9	+4.6	+3.9
5	Bernard Herrmann	6	89.3	+7.2	+3.9
6	Éric Serra	4	84.3	+4.2	+3.7
7	Cliff Martinez	14	74.3	+3.6	+3.3
8	John Murphy	6	75.5	+2.6	+3.2
9	Randy Newman	16	75.1	+4.3	+3.2
10	Jonny Greenwood	7	89.1	+7.9	+3.1
11	Wojciech Kilar	3	88	+4.1	+3
12	Philip Glass	6	81.7	+4.7	+3
13	Warren Ellis	8	81.8	+5.7	+2.9
14	Alex North	6	81.8	+4.7	+2.9
15	Elmer Bernstein	10	78	+4.7	+2.8

Composers Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Christopher Young	10	48.6	−8.6	−6.4
2	Graeme Revell	12	51.5	−8	−6
3	Brian Tyler	16	51.1	−9.4	−5.8
4	Steve Jablonsky	5	42	−7.5	−4.9
5	Mervyn Warren	3	34.7	−6.6	−4.5
6	John Powell	29	61.5	−4.3	−4.4
7	Aaron Zigman	3	34.3	−6.7	−4.4
8	Randy Edelman	8	52.8	−5.9	−4.4

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Howard Shore 29 films +11.8 → +6.8
Jonny Greenwood 7 films +7.9 → +3.1
Carter Burwell 40 films +6 → +1.9
Robbie Robertson 5 films +5 → +1.4
Bernard Herrmann 6 films +7.2 → +3.9
Trent Reznor 11 films +3.8 → +0.6

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Roc Chen 3 films −6.3 → −2.3
Trevor Rabin 10 films −6.9 → −3
Larry Groupé 5 films −7 → −3.2
Brian Tyler 16 films −9.4 → −5.8
Henry Jackman 15 films −5 → −1.5
Chris Hajian 4 films −7.6 → −4.1

Stars Who Add the Most

Points a film gains, on average, for having them billed in the top 3 · 3+ films

#	Name	Films	Avg.	Alone	Credit
1	Ralph Fiennes	11	80.2	+6	+4.9
2	Willem Dafoe	10	79	+5.2	+4.7
3	Joe Pesci	8	86	+7.4	+4.4
4	Ryan Gosling	14	75	+4	+4.2
5	Tim Robbins	8	77.9	+4.1	+4.1
6	Christopher Plummer	8	79.5	+4.8	+4
7	Dennis Hopper	6	82.2	+4.9	+4
8	Joaquin Phoenix	7	82.6	+5.5	+4
9	Rupert Grint	9	82.2	+6.3	+3.9
10	Carey Mulligan	6	85	+5.8	+3.9
11	Daniel Radcliffe	13	78.6	+5.7	+3.7
12	John Travolta	9	77	+4	+3.7
13	Jack Black	11	77	+4.5	+3.7
14	Jack Nicholson	7	87	+7.2	+3.6
15	James Stewart	9	79.9	+5.3	+3.6

Stars Who Cost the Most

Worst first

#	Name	Films	Avg.	Alone	Credit
1	Mark Wahlberg	19	51.8	−9.6	−6.3
2	Halle Berry	7	44.3	−8.6	−5.9
3	Pierce Brosnan	10	50.8	−7.6	−5.6
4	Bobby Cannavale	4	33.3	−8.6	−5.6
5	Sean Penn	15	55.6	−6.7	−5.4
6	John Boyega	4	42.5	−6.3	−5.3
7	Faye Dunaway	7	51.6	−5.9	−5
8	Sam Elliott	3	37.3	−6.1	−4.8

Flattered by Their Average

Credit that moved to the people they worked with · Alone → Credit

Leonardo DiCaprio 18 films +7.8 → +2.8
Ian McKellen 10 films +4.3 → −0.7
Frances McDormand 11 films +7.4 → +3.4
Viggo Mortensen 12 films +7.2 → +3.5
Philip Seymour Hoffman 11 films +5.8 → +2.1
Julie Delpy 7 films +6.7 → +3.2

Undersold by Their Average

Blame that moved to the people they worked with · Alone → Credit

Mark Wahlberg 19 films −9.6 → −6.3
Robert Downey Jr. 17 films −2.7 → +0.6
Bobby Cannavale 4 films −8.6 → −5.6
Geoffrey Rush 6 films −6.9 → −3.9
Penélope Cruz 5 films −6.9 → −4
Orlando Bloom 5 films −4.3 → −1.5

Chemistry

Better Together

The equation adds people up. If a partnership is worth more (or less) than its parts, it shows as a leftover: films that keep beating (or missing) the prediction whenever these people are together. Partners need 3+ films together and 2+ each apart, because a pair who only ever work together can't be compared with anything. People sharing exactly the same films are grouped. Scored as leftover ÷ (films + λ), from 689 teams.

More Than the Sum

Together, their films beat the prediction

George Lucas WriterHarrison Ford Star +4.5
7 films together · average +12.1 vs. prediction
- Indiana Jones and the Last Crusade 1989 96 vs. 78.2
- Raiders of the Lost Ark 1981 100 vs. 83
- Indiana Jones and the Temple of Doom 1984 97 vs. 77.7
- Indiana Jones and the Kingdom of the Crystal Skull 2008 72 vs. 68.2
- Star Wars 1977 89 vs. 78.8
- The Empire Strikes Back 1980 91 vs. 83.8
- Return of the Jedi 1983 91 vs. 81.6
John Williams ComposerHarrison Ford Star +3.7
11 films together · average +7.7 vs. prediction
- Indiana Jones and the Last Crusade 1989 96 vs. 78.2
- Raiders of the Lost Ark 1981 100 vs. 83
- Indiana Jones and the Temple of Doom 1984 97 vs. 77.7
- Indiana Jones and the Kingdom of the Crystal Skull 2008 72 vs. 68.2
- Star Wars 1977 89 vs. 78.8
- The Empire Strikes Back 1980 91 vs. 83.8
- Return of the Jedi 1983 91 vs. 81.6
- Star Wars: The Force Awakens 2015 93 vs. 77.1
- Presumed Innocent 1990 65 vs. 68.2
- Sabrina 1995 47 vs. 55.7
- Indiana Jones and the Dial of Destiny 2023 66 vs. 69.9
Steven Spielberg DirectorGeorge Lucas WriterMichael Kahn EditorHarrison Ford Star +3.6
4 films together · average +14.5 vs. prediction
- Indiana Jones and the Last Crusade 1989 96 vs. 78.2
- Raiders of the Lost Ark 1981 100 vs. 83
- Indiana Jones and the Temple of Doom 1984 97 vs. 77.7
- Indiana Jones and the Kingdom of the Crystal Skull 2008 72 vs. 68.2
Steven Spielberg DirectorGeorge Lucas WriterDouglas Slocombe CinematographerMichael Kahn EditorJohn Williams ComposerHarrison Ford Star +3.6
3 films together · average +18.1 vs. prediction
- Indiana Jones and the Last Crusade 1989 96 vs. 78.2
- Raiders of the Lost Ark 1981 100 vs. 83
- Indiana Jones and the Temple of Doom 1984 97 vs. 77.7
Christopher Nolan WriterWally Pfister Cinematographer +3.6
6 films together · average +10.8 vs. prediction
- The Dark Knight Rises 2012 85 vs. 75.4
- Memento 2000 96 vs. 83.5
- The Dark Knight 2008 94 vs. 81.3
- Batman Begins 2005 86 vs. 73.8
- Inception 2010 90 vs. 77.2
- The Prestige 2006 87 vs. 81.9
Christopher Nolan DirectorWally Pfister Cinematographer +3.4
7 films together · average +9.3 vs. prediction
- Insomnia 2002 79 vs. 78.5
- The Dark Knight Rises 2012 85 vs. 75.4
- Memento 2000 96 vs. 83.5
- The Dark Knight 2008 94 vs. 81.3
- Batman Begins 2005 86 vs. 73.8
- Inception 2010 90 vs. 77.2
- The Prestige 2006 87 vs. 81.9
Wally Pfister CinematographerLee Smith Editor +3.1
5 films together · average +10.5 vs. prediction
- The Dark Knight Rises 2012 85 vs. 75.4
- The Dark Knight 2008 94 vs. 81.3
- Batman Begins 2005 86 vs. 73.8
- Inception 2010 90 vs. 77.2
- The Prestige 2006 87 vs. 81.9
Richard Linklater DirectorRichard Linklater WriterSandra Adair EditorEthan Hawke Star +3.1
6 films together · average +9.4 vs. prediction
- Waking Life 2001 100 vs. 84.1
- Before Sunrise 1995 92 vs. 84.1
- Before Sunset 2004 90 vs. 85.7
- Before Midnight 2013 91 vs. 82.3
- Boyhood 2014 100 vs. 82.3
- The Newton Boys 1998 79 vs. 77
Martin Scorsese DirectorThelma Schoonmaker EditorRobert De Niro Star +3.1
7 films together · average +8.3 vs. prediction
- Raging Bull 1980 100 vs. 86.4
- The King of Comedy 1983 88 vs. 80.8
- Casino 1995 94 vs. 85.2
- GoodFellas 1990 92 vs. 83.8
- The Irishman 2019 94 vs. 84.5
- Cape Fear 1991 86 vs. 84.3
- Killers of the Flower Moon 2023 95 vs. 85.7
Oliver Wood CinematographerJohn Powell Composer +3
4 films together · average +11.9 vs. prediction
- The Bourne Ultimatum 2007 87 vs. 76
- The Bourne Supremacy 2004 84 vs. 71.7
- The Bourne Identity 2002 81 vs. 69.4
- Face/Off 1997 88 vs. 75.2

Less Than the Sum

Together, their films fall short of it

Ridley Scott DirectorSteven Zaillian Writer −3.8
3 films together · average −19 vs. prediction
- American Gangster 2007 69 vs. 65
- Hannibal 2001 8 vs. 48.4
- Exodus: Gods and Kings 2014 29 vs. 49.6
Dean Semler CinematographerWilliam Hoy Editor −3.4
3 films together · average −16.8 vs. prediction
- The Bone Collector 1999 38 vs. 53.2
- Dances with Wolves 1990 74 vs. 66.7
- We Were Soldiers 2002 4 vs. 46.4
Steven Zaillian WriterSean Penn Star −3.3
3 films together · average −16.6 vs. prediction
- The Falcon and the Snowman 1985 49 vs. 52.4
- The Interpreter 2005 33 vs. 48.8
- All the King's Men 2006 17 vs. 47.5
Jim Denault CinematographerJon Poll Editor −3.3
3 films together · average −16.6 vs. prediction
- Dinner for Schmucks 2010 54 vs. 56.4
- The Campaign 2012 54 vs. 57.7
- Coastal Elites 2020 3 vs. 46.8
Ted Elliott WriterTerry Rossio WriterHans Zimmer Composer −3.2
3 films together · average −16 vs. prediction
- Pirates of the Caribbean: At World's End 2007 29 vs. 52.1
- Pirates of the Caribbean: On Stranger Tides 2011 37 vs. 47.3
- Pirates of the Caribbean: Dead Man's Chest 2006 38 vs. 52.5
Barry Levinson DirectorRobert De Niro Star −3
3 films together · average −15 vs. prediction
- Sleepers 1996 43 vs. 68.1
- The Wizard of Lies 2017 70 vs. 62.8
- What Just Happened 2008 27 vs. 54
Peter S. Elliot EditorChristopher Lennertz Composer −2.9
3 films together · average −14.7 vs. prediction
- Shaft 2019 36 vs. 43.4
- Tom & Jerry 2021 12 vs. 41
- Back in Action 2025 49 vs. 56.7
George Clooney DirectorMartin Ruhe Cinematographer −2.8
3 films together · average −13.9 vs. prediction
- The Midnight Sky 2020 16 vs. 51.1
- The Tender Bar 2021 45 vs. 51.2
- The Boys in the Boat 2023 55 vs. 55.3
Dariusz Wolski CinematographerJohnny Depp Star −2.8
5 films together · average −9.4 vs. prediction
- Alice in Wonderland 2010 29 vs. 51
- Pirates of the Caribbean: At World's End 2007 29 vs. 52.1
- Pirates of the Caribbean: On Stranger Tides 2011 37 vs. 47.3
- Pirates of the Caribbean: The Curse of the Black Pearl 2003 79 vs. 55.9
- Pirates of the Caribbean: Dead Man's Chest 2006 38 vs. 52.5
Max Steiner ComposerOlivia de Havilland Star −2.7
4 films together · average −10.7 vs. prediction
- Gold Is Where You Find It 1938 55 vs. 60.4
- Dodge City 1939 69 vs. 55.8
- Santa Fe Trail 1940 8 vs. 52
- They Died with Their Boots On 1941 49 vs. 55.7

Show Your Working

The Breakdowns

Any film taken apart into its credits, and any person's bonus rebuilt from their films

One Film

Baseline plus each person's bonus gives the prediction; the rest is the film itself

Film

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One Person

On each film: the rating, minus the prediction from everyone else. Add up, divide by films + λ

Person

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The Fine Print

How It Works

Why a Bonus Isn't an Average

An editor who cuts most of their films for a great director has a high average, and some of that belongs to the director. The equation handles this because every bonus is fitted at the same time. Nudge one person's bonus up and the prediction for each of their films goes up by the same amount. That helps if their films were mostly under-predicted and hurts if they were over-predicted. The answer is where no nudge helps anyone, which means each person's films, after everyone else's bonus is counted, are neither under- nor over-predicted on balance (allowing for λ).

No two films differ by only one person, so there is never a clean side-by-side comparison. The comparison comes from combining films: add and subtract enough of them and everyone except one person cancels out. The more people move between different teams, the more such combinations exist and the sharper the bonus.

Choosing λ. The films were split into 5 groups. Each group in turn was hidden, the model was fitted on the rest, and it predicted the hidden ratings. The λ with the smallest miss is used. Guessing the average for every film misses by 15.1 points:

λ	Avg. miss	Typical miss (RMS)
Guess 67.6 every time	15.1	19.2
2	14.63	18.95
4	14.44	18.67
8	14.34	18.49
12 ← used	14.34	18.45
20	14.38	18.47

On films it has already seen, the equation misses by 8.8 points on average. On films it hasn't seen, it only does a little better than guessing. That's expected: most people in the log appear once or twice, so a new film usually brings almost no information about its crew. The bonuses mean the most for people with many films.

What It Can't Do

Tell apart people who always work together. If two people share every film, no combination of films separates them, so the bonus is split between them. These are the largest such groups with 3+ films:

Danny Bensi Composer · Saunder Jurriaans Composer 11 films · −3.2 between them
Robert Wade Writer · Neal Purvis Writer 9 films · −0.9 between them
John Francis Daley Writer · Jonathan Goldstein Writer 7 films · 0 between them
Jonathan Aibel Writer · Glenn Berger Writer 7 films · −0.8 between them
Rick Jaffa Writer · Amanda Silver Writer 6 films · +0.5 between them
John Brancato Writer · Michael Ferris Writer 6 films · −6.5 between them
Brooke Blair Composer · Will Blair Composer 5 films · +1.5 between them
John Glen Director · Michael G. Wilson Writer 5 films · +1.7 between them
Alex Kurtzman Writer · Roberto Orci Writer 5 films · −0.6 between them
Damien Chazelle Director · Justin Hurwitz Composer 5 films · +3.8 between them
Joe Russo Director · Anthony Russo Director 5 films · −4.6 between them
Stephen McFeely Writer · Christopher Markus Writer 5 films · −2.8 between them

Capture chemistry. The equation assumes a person adds the same amount whoever they work with. Partnerships that break that rule show up in Better Together, not in the bonuses.

Prove cause. A bonus means "films with this person get more points from me than their co-workers explain." A cinematographer may simply choose good scripts. It describes your ratings, not the craft.