Predicting Board Game Collections

ZeeGarcia’s Collection

Author

Phil Henrickson

Published

May 21, 2025

About

This report details the results of training and evaluating a classification model for predicting games for a user’s boardgame collection.

Note

To view games predicted by the model, go to Section 5.

Collection

The data in this project comes from BoardGameGeek.com. The data used is at the game level, where an individual observation contains features about a game, such as its publisher, categories, and playing time, among many others.

I train a classification model at the user level to learn the relationship between game features and games that a user owns - what predicts a user’s collection?

username status games
ZeeGarcia ever_owned 1975
ZeeGarcia own 435
ZeeGarcia rated 2512

I evaluate the model’s performance on a training set of historical games via resampling, then validate the model’s performance on a set aside set of newer relases. I then refit the model on the training and validation in order and predict upcoming releases in order to find new games that the user is most likely to add to their collection.

username years type
Own
no yes
ZeeGarcia -3500-2021 train 26085 277
ZeeGarcia 2022-2023 valid 10203 105
ZeeGarcia 2024-2028 test 8540 53

Types of Games

What types of game does the user own? The following plot displays the most frequent publishers, mechanics, designers, artists, etc that appear in a user’s collection.

Show the code
collection |>
    filter(own == 1) |>
    collection_by_category(
        games = games_raw
    ) |>
    plot_collection_by_category() +
    ylab("feature")

The following plot shows the years in which games in the user’s collection were published. This can usually indicate when someone first entered the hobby.

Games in Collection

What games does the user currently have in their collection? The following table can be used to examine games the user owns, along with some helpful information for selecting the right game for a game night!

Use the filters above the table to sort/filter based on information about the game, such as year published, recommended player counts, or playing time.

Show the code
collection |>
    filter(own == 1) |>
    prep_collection_datatable(
        games = games_raw
    ) |>
    filter(!is.na(image)) |>
    collection_datatable()

Modeling

I’ll now the examine predictive models trained on the user’s collection.

For an individual user, I train a predictive model on their collection in order to predict whether a user owns a game. The outcome, in this case, is binary: does the user have a game listed in their collection or not? This is the setting for training a classification model, where the model aims to learn the probability that a user will add a game to their collection based on its observable features.

How does a model learn what a user is likely to own? The training process is a matter of examining historical games and finding patterns that exist between game features (designers, mechanics, playing time, etc) and games in the user’s collection.

I make use of many potential features for games, the vast majority of which are dummies indicating the presence or absence of the presence or absence of things such as a publisher/artist/designer. The “standard” BGG features for every game contain information that is typically listed on the box its playing time, player counts, or its recommended minimum age.

Note

I train models to predict whether a user owns a game based only on information that could be observed about the game at its release: playing time, player count, mechanics, categories, genres, and selected designers, artists, and publishers. I do not make use of BGG community information, such as its average rating, weight, or number of user ratings. This is to ensure the model can predict newly released games without relying on information from the BGG community.

What Predicts A Collection?

A predictive model gives us more than just predictions. We can also ask, what did the model learn from the data? What predicts the outcome? In the case of predicting a boardgame collection, what did the model find to be predictive of games a user has in their collection?

To answer this, I examine the coefficients from a model logistic regression with ridge regularization (which I will refer to as a penalized logistic regression).

Positive values indicate that a feature increases a user’s probability of owning/rating a game, while negative values indicate a feature decreases the probability. To be precise, the coefficients indicate the effect of a particular feature on the log-odds of a user owning a game.

The following visualization shows the path of each feature as it enters the model, with highly influential features tending to enter the model early with large positive or negative effects. The dotted line indicates the level of regularization that was selected during tuning.

Show the code
#|
model_glmnet |>
    pluck("wflow", 1) |>
    trace_plot.glmnet(max.overlaps = 30) +
    facet_wrap(~ params$username)

Partial Effects

What are the effects of individual features?

Use the buttons below to examine the effects different types of predictors had in predicting the user’s collection.

Assessment

How well did the model do in predicting the user’s collection?

This section contains a variety of visualizations and metrics for assessing the performance of the model(s). If you’re not particularly interested in predictive modeling, skip down further to the predictions from the model.

The following displays the model’s performance in resampling on a training set, a validation set, and a holdout set of upcoming games.

Show the code
metrics |>
    mutate_if(is.numeric, round, 3) |>
    pivot_wider(
        names_from = c(".metric"),
        values_from = c(".estimate")
    ) |>
    gt::gt() |>
    gt::sub_missing() |>
    gt_options()
username wflow_id type .estimator mn_log_loss roc_auc pr_auc
ZeeGarcia glmnet resamples binary 0.045 0.892 0.145
ZeeGarcia glmnet test binary 0.036 0.870 0.073
ZeeGarcia glmnet valid binary 0.044 0.900 0.162

An easy way to visually examine the performance of classification model is to view a separation plot.

I plot the predicted probabilities from the model for every game (during resampling) from lowest to highest. I then overlay a blue line for any game that the user does own. A good classifier is one that is able to separate the blue (games owned by the user) from the white (games not owned by the user), with most of the blue occurring at the highest probabilities (left side of the chart).

Show the code
preds |>
    filter(type %in% c("resamples", "valid")) |>
    plot_separation(outcome = params$outcome)

I can more formally assess how well each model did in resampling by looking at the area under the ROC curve (roc_auc). A perfect model would receive a score of 1, while a model that cannot predict the outcome will default to a score of 0.5. The extent to which something is a good score depends on the setting, but generally anything in the .8 to .9 range is very good while the .7 to .8 range is perfectly acceptable.

Show the code
preds |>
    nest(data = -c(username, wflow_id, type)) |>
    mutate(
        roc_curve = map(
            data,
            safely(~ .x |> safe_roc_curve(truth = params$outcome))
        )
    ) |>
    mutate(result = map(roc_curve, ~ .x |> pluck("result"))) |>
    select(username, wflow_id, type, result) |>
    unnest(result) |>
    plot_roc_curve()

Top Games in Training

What were the model’s top games in the training set?

Show the code
preds |>
    filter(type == "resamples") |>
    prep_predictions_datatable(
        games = games,
        outcome = params$outcome
    ) |>
    predictions_datatable(
        outcome = params$outcome,
        remove_description = T,
        remove_image = T,
        pagelength = 15
    )

Top Games in Validation

What were the model’s top games in the validation set?

Show the code
preds |>
    filter(type %in% c("valid")) |>
    prep_predictions_datatable(
        games = games,
        outcome = params$outcome
    ) |>
    predictions_datatable(
        outcome = params$outcome,
        remove_description = T,
        remove_image = T,
        pagelength = 15
    )

Top Games by Year

Displaying the model’s top games for individual years in recent years.

Show the code
preds |>
    filter(type %in% c("resamples", "valid")) |>
    top_n_preds(
        games = games,
        outcome = params$outcome,
        top_n = 15,
        n_years = 15
    ) |>
    gt_top_n(collection = collection |> prep_collection())
Rank 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
1 Dice Town 7 Wonders Takenoko Mage Wars Arena Lewis & Clark: The Expedition Abyss 7 Wonders Duel Conan Gloomhaven Château Aventure Cthulhu: Death May Die Furnace Moving Pictures Sea Salt & Paper Welcome To...: Collector's Edition
2 Mr. Jack in New York Hanabi Mage Knight Board Game Robinson Crusoe: Adventures on the Cursed Island Eldritch Horror Five Tribes: The Djinns of Naqala Pandemic Legacy: Season 1 Reign of Cthulhu Circle the Wagons Rising Sun Deep Blue Puerto Rico Sleeping Gods Frosthaven Empire's End
3 Finca Earth Reborn Ninjato Escape: The Curse of the Temple Longhorn Pandemic: The Cure Arboretum Scythe DIG Everdell Wingspan Pandemic Legacy: Season 0 Pandemic: Hot Zone – Europe Knight Fall Arkeis
4 Cyclades Forbidden Island Mundus Novus Libertalia Legacy: The Testament of Duke de Crecy Imperial Settlers Raptor Iberia Pandemic Legacy: Season 2 Root Trails of Tucana Via Magica Flourish Tribes of the Wind Numbsters
5 Endeavor Troyes Summoner Wars: Master Set Ginkgopolis City of Iron Port Royal Mission: Red Planet (Second/Third Edition) Arkham Horror: The Card Game Meeple Circus Legendary Encounters: The X-Files Deck Building Game Naga Raja Gloomhaven: Jaws of the Lion Cascadia Endless Winter: Paleoamericans Earth
6 Jaipur Glen More Puerto Rico Fleet Forbidden Desert Madame Ching Trambahn When I Dream Near and Far Seals The Magnificent Hues and Cues Botanik Amsterdam Ticket to Ride Legacy: Legends of the West
7 Long Shot Merchants & Marauders Elder Sign Love Letter SOS Titanic Artifacts, Inc. GEM Dice Stars Mythic Battles: Pantheon Treasure Island Antinomy Nidavellir Tides Hamburg Naturopolis
8 Kuhhandel Master Innovation The New Era Seasons Ghooost! AquaSphere The Little Prince: Rising to the Stars Kanagawa Smile Micropolis Herbaceous Sprouts Top Ten Ankh: Gods of Egypt Marvel Zombies: Heroes' Resistance 51st State: Ultimate Edition
9 La Habana Hive Pocket The City Descent: Journeys in the Dark (Second Edition) Bruges Nyakuza Blood Rage Legendary Encounters: A Firefly Deck Building Game Pandemic: Rising Tide Yellow & Yangtze Aftermath Forgotten Waters ROVE: Results-Oriented Versatile Explorer Revive Expeditions
10 Claustrophobia Merkator Tournay Star Wars: The Card Game Eight-Minute Empire: Legends Dragon Run ...and then, we held hands. Islebound WOO Architects of the West Kingdom Draftosaurus Planet Apocalypse Arkham Horror: The Card Game (Revised Edition) Wildtails: A Pirate Legacy Sleeping Gods: Distant Skies
11 Macao Tikal II: The Lost Temple Timeline: Science & Discoveries Il Vecchio The Little Prince: Make Me a Planet Blue Moon Legends Vs System 2PCG: The Marvel Battles Terraforming Mars Azul Fall of Rome Siege of the Citadel Deep Vents Batman: The Animated Series Adventures – Shadow of the Bat Wayfarers of the South Tigris Fire for Light
12 Warhammer: Invasion Mousquetaires du Roy Tales & Games: The Hare & the Tortoise Eight-Minute Empire Pathfinder Adventure Card Game: Rise of the Runelords – Base Set Heroes Wanted Viticulture Essential Edition Vs System 2PCG: The Defenders Herbaceous Arkham Horror (Third Edition) Tapestry Viscounts of the West Kingdom Marvel United: X-Men Nemesis: Lockdown 51st State: Ultimate Edition (Gamefound Edition)
13 Einauge sei wachsam! 51st State Friday Antartik Corto Desperados of Dice Town Tokaido: Deluxe Edition Quadropolis RUM The River Pandemic: Rapid Response Lost Ruins of Arnak Sobek: 2 Players Now or Never Sleeping Gods: Primeval Peril
14 Martinique Luna Mansions of Madness Shadows over Camelot: The Card Game Terror in Meeple City Red7 Plums Pocket Madness The Godfather: Corleone's Empire Zombicide: Green Horde Tang Garden Sleeping Gods: Primeval Peril Bullet♥︎ Everdell: The Complete Collection The Castles of Burgundy: Special Edition
15 Food Chain GOSU Mondo Gentlemen Thieves Cinque Terre Isle of Trains Elysium Mansions of Madness: Second Edition Legendary Forests Underwater Cities Tainted Grail: The Fall of Avalon Food Chain Island King of Tokyo: Monster Box 1001 Islands Forbidden Jungle

Predictions

New and Upcoming Games

What were the model’s top predictions for new and upcoming board game releases?

Show the code
new_preds |>
    filter(type == "upcoming") |>
    # imposing a minimum threshold to filter out games with no info
    filter(usersrated >= 1) |>
    # removing this goddamn boxing game that has every mechanic listed
    filter(game_id != 420629) |>
    prep_predictions_datatable(
        games = games_new,
        outcome = params$outcome
    ) |>
    predictions_datatable(outcome = params$outcome)

Older Games

What were the model’s top predictions for older games?