The decoy effect is a cognitive bias that means people can change their preference between two choices when a third (decoy) option is introduced. The decoy has to be clearly inferior in all respects to one of the offers and inferior in some respects to the other option to make them look more attractive.
In the example below the introduction of the middle plan (Print only subscription) draws attention away from the digital only plan. It persuades more users to choose the more expensive plan. The decoy (print only) makes the digital + print subscription look more appealing. The digital only plan appears to be a foolish option.
Below is an example of decoy offer from The Financial Times. Notice the “Print Trial” offer is the same as the “Print and Digital” package so there is no real benefit in the former plan. As all choices are relative, the “Print Trial” helps make the other two plans appear more attractive. It should encourage more people to subscribe to the the “Premium Digital Trial” plan.
Conversion marketing – Glossary of Conversion Marketing.
Over 300 tools reviewed – Digital Marketing Toolbox.
A/B testing software – Which A/B testing tool should you choose?