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A Practical Guide To The Design Implementation And Evaluation Stages Of Food Safety Nudges

Hennessey, Mathew; Unger, Fred; Sinh, Dang Xuan; Phuc, Pham Duc; Tuan Hai, Ngo Hoang; Thanh Huyen, Le Thi; Hung, Pham Van; Hasler, Barbara


Mathew Hennessey

Fred Unger

Dang Xuan Sinh

Pham Duc Phuc

Ngo Hoang Tuan Hai

Le Thi Thanh Huyen

Pham Van Hung

Barbara Hasler


The field of nudge theory – influencing the way people make choices through subtle environmental change – has
been used to improve healthy food choices, but to date has not been extensively applied to the livestock and food
chain sector. In this document we present a practical guide to the design, implementation, and evaluation stages of
food safety nudges, using case studies from the SafePORK project in Vietnam to provide context for the discussion of
each stage.
We propose that the following five stages should be considered at the start of projects looking to implement food
safety nudges; 1) setting out the problem, 2) identifying relevant behaviours, 3) defining assumptions, 4) designing
the nudge, and 5) establishing evaluation design.
At the outset, clearly setting out the problem to be addressed allows identification of the expected outputs to be
observed. We suggest the application of a theory of change framework such as the one set out by Mayne (2015)
allowing examination of the various elements needed to achieve a behavioural change.
To identify and understand relevant behaviours to be changed we look to two psychological frameworks - the
theoretical domains framework (Atkins et al. 2017) and the COM-B model of behavioural change (Michie and West
2013). These frameworks provide insights into behavioural change and can be used to identify suitable nudges in
food safety interventions.
Defining assumptions allows the different steps and pathways within the theory of change to be connected.
Assumptions may be formed using a variety of existing evidence – published literature, expert opinion, surveys,
interviews, focal group discussions – i.e. the strength of evidence behind them can vary.
During the design of a food safety nudge we look to the following three frameworks; 1) the Nuffield intervention
ladder (Nuffield Council on Bioethics, 2007) to consider the level of intrusiveness exerted by the nudge, 2) the EAST
framework (Service et al. 2014) to increase the effectiveness of the nudge, and 3) the MINDSPACE framework (Dolan
et al. 2012) to consider which behavioural elements to target with the nudge.
Finally, establishing an evaluation design needs to consider the level of resources available. We discuss the
evaluation of food safety nudges in two scenarios, 1) where it is possible to implement a controlled before and after
or randomly controlled trial, and 2) when nudge interventions occur as part of a package of broader interventions
and alternative strategies of evaluation such as contribution analysis can be considered.
Consideration of the steps outlined in this document from the outset of behavioural nudge design will help to
design a nudge and to facilitate subsequent nudge evaluation, which otherwise, due to the inherent subtle nature of
nudges, can be challenging. Consequently, in planning projects which aim to use nudges, sufficient budget should
be allocated for the evaluation process, thus providing the opportunity to generate evidence on nudge effectiveness
for both current and future work.


Hennessey, M., Unger, F., Sinh, D. X., Phuc, P. D., Tuan Hai, N. H., Thanh Huyen, L. T., …Hasler, B. (2021). A Practical Guide To The Design Implementation And Evaluation Stages Of Food Safety Nudges. Addis Ababa: International Livestock Research Institute

Report Type Technical Report
Publication Date Nov 1, 2021
Deposit Date Jan 11, 2022
Publicly Available Date Jan 11, 2022
Public URL


Hennessey 2021 ILRI Manual 52 A Practical Guide To The Design Implementation And Evaluation Stages Of Food Safety Nudges (5.7 Mb)

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