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Use the GDC 2021 Session Viewer to browse and sort the ever-growing list of sessions by day, time, pass type, topic, and format. All registered attendees will be able to build their personal schedule directly within the event platform, once live early July 2021. All times are listed in Pacific Time.

Sigmoids for Storytellers: Mathematical Solutions to Narrative Problems

Emily Short  (Creative Director, Failbetter Games)

Date: Friday, July 23

Time: 9:40am - 10:40am

Pass Type: All Access Pass, Core Pass

Topic: Design

Format: Session

Vault Recording: Video

Audience Level: I acknowledge GDC 2021 is an all-digital event and commit to participating virtually.

Many narrative design tasks might appear numbers-light, focused more on story structures than on calculations or equations.

But numeric considerations do creep in, whether we're designing trait-based dialogue systems, incorporating randomised stat tests, or tying story pace to the meta progression in a free-to-play title. Soon it becomes useful to have some mathematical tools at our disposal – including familiarity with different types of randomness, assorted functions to calculate difficulties and rewards, and strategies for turning the player's whole action history into useful stats.

This talk introduces a number of systems design techniques for narrative games, drawing on detailed examples from Failbetter's long-running Fallen London and elsewhere. It offers resources for further learning, and ends with guidance on how to provide tooling, training, and documentation to help even the numbers-averse members of a writing team make the most of these methods.


Narrative designers will learn about what systems design involves, how it applies to narrative problems, and some specific numerical methods that can enrich their work. Systems designers will learn about the systemic depth possible in narrative.

Intended Audience

This talk is appropriate for narrative designers who do some systemic design or expect that they'll need to in the future; systems designers curious about the less linear aspects of narrative design; and tool creators who support systemic narrative work. Strong math skills are not a prerequisite.