Affordance design
Affordance design is the work of building and shipping the things a user can reach for at a moment in their pursuit (a button, a screen, a default setting, an email, a doc, whatever form fits the gap) so each one actually helps with what the user is trying to do right then. The work runs across three separate questions: whether to build anything at this gap at all, what form the thing should take, and how to make that thing work well at the moment the user encounters it. Each is its own area of practice with its own heuristics, not a single sequential decision.
Definition
The practitioner work of populating a critical route with affordances — deciding which sub-transitions warrant an intervention, choosing what to build, and designing it to fit the user's pursuit at that step.
In plain language
Affordance design is the hands-on work of building the things users encounter on their way to value: buttons, emails, wizards, help docs, features, onboarding flows. A team makes three calls at each step: whether to build anything there at all or leave the user to figure it out on their own, what form to use (a feature? an email? a doc? a video?), and once a form is picked, whether the thing actually works for the user at the moment they show up to it.
Where the work fits
Critical route work identifies the sub-transitions that must hold for the user to reach their sought state. Route efficacy establishes what makes routes traversable — reachability, phenomenology, completion traversal, affordance matching. Affordance design is the complementary work: given a route's shape, what do you actually build to facilitate each sub-transition?
The work runs only on sub-transitions that survive the four-filter test at their scale. A sub-transition that fails the filter doesn't get affordance investment regardless of how well it could be designed.
The three phases
The work proceeds in three sequential decisions, each with its own apparatus:
- Deciding whether to build at all. Every gap between sub-transitions is an implicit choice: either provide an affordance, or pass the burden of step-efficacy to the user. The figure-it-out anti-pattern names the default of leaving sub-transitions for the user to produce themselves. Sub-transition leverage analysis identifies which structurally-valid sub-transitions have the biggest drop-off gap and most actionable intervention available.
- Choosing what to ship. Once a sub-transition warrants an affordance, multiple interventions are usually possible. The five-question intervention selection heuristic scores candidates on intent fidelity, reassurance value, organizational feasibility, feedback speed, and evolution path. Path investment discipline starts with the cheapest, most reversible intervention and deepens only on evidence. Affordance-type reframing breaks default assumptions about what form the intervention should take.
- Designing it well. CARE-FU surfaces gaps in Context, Action, Response, Enhancement, and Follow-Up at the affordance level. Summoning-aware defaults checks that the affordance's state on arrival matches what its summoning context implies about the user's route-step. Cross-channel coherence verifies that intent-specific affordances span every channel the user encounters. Collapsing sub-transitions looks for opportunities to fold a step out of the user's experience by absorbing it into the affordance. Intent mirroring is often the cheapest high-ratio move — small affordance elements that echo the user's declared intent back in their own vocabulary.
Heuristics that surface gaps
Affordance-design heuristics operate at a different register than route-efficacy conditions. Reachability, phenomenology, completion traversal, and affordance matching are necessary conditions — derivable from first principles, with failure at any of them producing a failure that can be diagnosed structurally. The affordance-design heuristics are practitioner operations that reliably surface design gaps when run, but don't individually define what makes an affordance succeed.
An affordance missing one letter of CARE-FU doesn't automatically fail; an affordance nailing all five doesn't automatically succeed. The discipline is in running the checks consistently, not in treating any of them as gatekeepers. The same applies to summoning-aware defaults, cross-channel coherence, and the rest: they catch holes the team would otherwise ship past.
Example
A SaaS team identifies signup-to-first-invoice-sent as a high-drop-off sub-transition on the critical route. The figure-it-out anti-pattern would leave the user to find invoice creation themselves; the team decides this gap warrants an explicit affordance.
Three candidates surface: a lifecycle email nudging invoice creation, a post-signup wizard that walks the user through it, and an in-app banner with a CTA. The five-question heuristic favors the banner — lowest organizational overhead, fastest feedback, clearest evolution path. Baby pokemon discipline ratifies starting there before investing in a wizard.
CARE-FU then surfaces a Context gap: the banner reads "Create your first invoice" without communicating why doing it now benefits the user. The team rewrites the copy to anchor on the sought state ("Send your first invoice in under a minute — we'll guide you"). Summoning-aware defaults catches a second gap: the banner shows the same prompt to users arriving from invoice-specific ad creative as to users arriving from a generic homepage signup. The team branches the copy by acquisition source.
What started as "let's build a wizard" ended as a single copy change in a banner the team already had — driven by working through the three phases in order rather than skipping to the largest-form intervention.