The Decoy Effect (Asymmetric Dominance)

The Science Behind The Decoy Effect (Asymmetric Dominance)

The Decoy Effect, also known as Asymmetric Dominance, describes a fascinating quirk in human decision-making: when we are choosing between two options, the introduction of a third option, strategically designed to be inferior to one of the original two, can dramatically shift which option we choose. The 'decoy' doesn't win. It isn't supposed to. Its entire job is to make one of the other options look comparatively brilliant. This principle was formally identified and named by researchers Joel Huber, John Payne, and Christopher Puto in a landmark 1982 paper published in the Journal of Consumer Research, where they demonstrated that adding an asymmetrically dominated option to a choice set reliably increased the preference share of the target option.

The psychology behind this effect runs deep. Human beings are not natural absolute thinkers, we are wired to make relative judgements. We rarely evaluate whether a price is 'good' in isolation; instead, we look sideways at the other options on the table and ask, 'compared to what?' This is why a $750 treatment pack can feel like a bargain or an extravagance depending entirely on what's sitting next to it on your pricing menu. The decoy works by providing a reference point that makes the comparison obvious, removing the cognitive effort required to evaluate value independently. Your patient's brain, presented with three clear options, does the maths automatically and arrives at a conclusion that feels self-generated rather than suggested.

Dan Ariely, the behavioural economist at Duke University whose 2008 book 'Predictably Irrational' brought this principle to a mainstream audience, demonstrated repeatedly that people believe they are making rational, self-determined choices when they are, in fact, being profoundly influenced by the architecture of the options presented to them. Ariely's central argument is that irrationality in human decision-making is not random, it is systematic and predictable. Which means it can be designed around, ethically, to guide people toward decisions that genuinely serve their interests. For allied health practitioners, this is not about manipulation; it's about removing the friction that causes patients to default to inaction when the evidence clearly supports continued care.

What makes the Decoy Effect particularly powerful in a healthcare context is that the stakes of the decision are real. A patient who disengages prematurely from physiotherapy after an acute injury, or drops off from chiropractic care before a maintenance programme takes hold, often experiences a return of symptoms weeks or months later. The cost of non-completion is borne by the patient, not just the practice. Structuring your rebooking offers to nudge patients toward longer-term commitment is therefore an act of clinical integrity as much as it is a revenue strategy, provided the treatment plan genuinely warrants it.

The Research

How to Apply This in Your Practice

To apply the Decoy Effect in your practice's patient re-engagement strategy, the first step is restructuring how you present rebooking options. Rather than sending a lapsed patient a message with a single call-to-action ('Book your next appointment for $95'), present a three-tier structure within your outreach communication. A well-constructed example might read: 'We'd love to help you get back on track. You can book a single session at $95, a pack of 5 sessions at $425 ($85 per session), or our most popular option, a pack of 10 sessions at $750 ($75 per session).' The five-session pack is your decoy. It's not a bad deal in absolute terms, but relative to the 10-session pack, it offers less savings per session and no meaningful advantage over the single session in terms of commitment signal. Its presence makes the 10-session pack feel like an obvious, intelligent choice.

The messaging around these options matters enormously. When you're reaching out to a patient who hasn't attended in 60, 90, or 120 days, you're not just selling an appointment, you're asking them to re-commit to a care journey they previously abandoned. Behavioural science tells us that commitment devices are powerful motivators, but patients need to feel they are choosing to commit rather than being pressured. Frame your outreach with clinical warmth first: 'Hi [Name], we noticed it's been a while since your last visit, and we want to make sure you're still feeling your best after your [knee/back/shoulder] treatment.' Then, in the same message or a follow-up, introduce the options naturally: 'When you're ready to rebook, here's how we make it easy...' followed by the three-tier structure. The language 'most popular' or 'best value' placed next to the target option (the 10-pack) reinforces the decoy's work without feeling pushy.

From a workflow perspective, this approach integrates naturally into automated re-engagement sequences. If your practice uses a platform to trigger outreach to lapsed patients at defined intervals, say, 30, 60, and 90 days post last-appointment, you can embed the three-tier offer into the 60-day touchpoint, when the patient is engaged enough to have opened earlier messages but hasn't yet committed to rebooking. SMS messages work well for the initial re-engagement, while email allows you to present the pricing structure with more visual clarity. If your booking system permits, link each of the three options directly to a checkout or booking page so the patient can act on whichever option they choose without friction. Remove every possible step between their decision and their confirmation.

It's important to ensure the decoy structure is grounded in genuine clinical rationale. If your clinical protocols genuinely support a 10-session plan for a patient's condition, and for many musculoskeletal presentations in physiotherapy, osteopathy, or chiropractic care, they do, then you are not manufacturing urgency. You are presenting a real treatment option in a way that makes its value legible. Allied health practitioners should audit their most common patient presentations and build tier structures that reflect actual treatment pathways. A podiatry practice dealing with chronic plantar fasciitis, for example, might structure tiers around initial assessment, a short-term management block, and a full rehabilitation and orthotic review programme. The decoy effect amplifies honest value, it doesn't conjure value that isn't there.

Seeing It in Action

Your Action Plan

1. 1Audit your current rebooking and re-engagement communications, identify any that present a single option or price point, and flag these as priority candidates for a three-tier restructure.
2. 2For your two or three most common patient presentations (e.g., lower back pain, sports injury, postural issues), design a clinically justified three-tier session package structure where the middle tier serves as a deliberate decoy by offering less per-session value than the top tier without a compelling additional benefit.
3. 3Update your re-engagement message templates, SMS and email, to introduce the three-tier options naturally after a warm, clinically grounded opening, and use labels like 'Best value' or 'Most popular' on the target (top-tier) option to provide social proof that reinforces the decoy's effect.
4. 4Ensure each option in your three-tier structure links directly to a friction-free booking or checkout page, so the patient can act immediately on whichever option the decoy has guided them toward, eliminating any delay between decision and confirmation.
5. 5Track conversion rates on your re-engagement sequences before and after implementing the three-tier structure, comparing both the percentage of lapsed patients who rebook and the average session-pack value selected, so you can refine your decoy positioning over time.