Nudge Theory

Leaf on water

Nudge nudge….

Providing a ‘nudge’, a small push in the right direction, certainly has an intuitive appeal to those tasked with trying to change water using behaviours. Asking people to make a big change to the way they live their lives can be challenging. A nudge is small, a nudge is simple, and this is why a nudge is so appealing. But does it work? Read more about Nudge Theory and how it might be useful  to you…

The Theory

"A nudge, as we will use the term, is any aspect of the choice architecture that alters people’s behavior in a predictable way without forbidding any options or significantly changing their economic incentives. To count as a mere nudge, the intervention must be easy and cheap to avoid." Thaler & Sunstein (2008), Nudge: Improving Decisions about Health, Wealth & Happiness

Nudge theory focusses on designing choices for people in a way that will encourage a particular decision. The theory assumes that people make mental short cuts and can be lazy in their decision making. By presenting choices in a certain way, people make ‘wiser’ decisions without losing their freedom of choice. The decision is still yours, but you are being nudged one way or the other.

There has been a lot of debate around what counts as a nudge and what does not, with the term often being mistakenly applied to any behavioural intervention targeting a small change. For our purposes we will consider nudging in two specific ways. Firstly where a chosen option is promoted in such a way as to influence choices, for example encouraging healthier eating by putting fruit at eye level in shops and cafes, or a different example many readers will have heard of is the piano stairs where walking up the stairs was made much more appealing than taking the escalator. Secondly, it is possible to nudge a decision a certain way by making the target behaviour the default setting and requiring individuals to opt out, for example auto enrolment for a workplace pension scheme.

Nudges are often employed alongside other behaviour change methods such as social norms or gamification.

The Good

The UK Government is certainly a fan of the ‘nudge’ approach, with their Behavioural Insights Team known as the ‘Nudge Unit’ being set up and dedicated to nudging people in a particular direction on a wide range of behaviours. A successful example in the UK is that of loft insulation – the scheme offering subsidised insulation was not very successful, but when the offer was changed to include free loft clearance (so removing a barrier to take up but also offering an appealing service) uptake improved dramatically. A recent review of green nudges illustrated that they can be effective, particularly when the ‘green’ option is made the default choice, for example in the case of paperless billing or automatic double sided printing in offices.

The Bad

Not everybody agrees that nudging is the right approach to changing behaviours. The most significant criticism is that a nudge is not transformative - choices are influenced by changing the context, but the behavioural change comes with no deeper change in terms of attitudes or beliefs. Nudging changes behaviour by stealth rather than engagement. Ironically this is probably also the reason that the approach is so popular. 

A House of Lords Review on the effectiveness of nudging concluded that nudges used in isolation will often not be effective in changing the behaviour of the population. Instead, a whole range of measures are needed to change behaviour in a way that will make a real difference. Today it is widely accepted that a nudge should be just one option in an arsenal of behaviour change tools (including the not quite so stealthy ‘shove’ – more on that another time!).

Using Nudge Theory for Water Efficiency

Wouldn’t it be great if we could make water efficiency the default setting? One idea could capitalise on the moment when people move home, they ring up their water company to register their new address or to give their meter reading, and at that point they are booked in for a ‘free water optimisation check’ for their new home. They are obviously free to refuse, but wouldn’t it make sense to have a qualified person check over their water using fixtures and fittings, making sure everything is performing to its optimum? And whilst there they could provide advice and water efficient gadgets if wanted.

Considering some of the concerns, Nudging  is an approach that may be best deployed for one-off decisions (meaning that a later change in context shouldn’t have a detrimental effect upon the water efficient change).  A good example would be purchasing water using appliances and fittings. Just like the fruit and vegetables being placed at eye level, water efficiency appliances such as washing machines and dishwashers, as well as smaller goods like shower heads and taps, could be made more prominent. This applies both in-store and on-line, and for both household retailers and plumbers merchants – water efficient products could be shown first, could be ‘recommended’ by the retailer or positioned prominently.

If you have applied Nudge Theory in your water efficiency work, or have an idea about how you might like to in the future, we would love to hear from you. Please email Dani at