Appendix D: Gaps in the evidence
The Public Health Interventions Advisory Committee (PHIAC) identified a number of gaps in the evidence related to the programmes under examination based on an assessment of the evidence and expert comment. These gaps are set out below.
1. There was very limited, UK‑based evidence on information provision, supply of resources and changes to the physical environment to protect against skin cancer caused by UV rays. (This includes multi‑component interventions.) The only available evidence either demonstrated a small effect size or did not provide detail about the population groups that benefited – or how messages should be framed for different population groups. (Source: Evidence reviews 1–5.)
2. Details were often missing from the descriptions of interventions to protect people against skin cancer. This included details on: content (such as what was delivered and by whom), how frequently and for how long the intervention was delivered, the economic costs and benefits, any variation in effectiveness and cost effectiveness in relation to factors such as age and ethnicity and how long the intervention was effective or cost‑effective. (Source: Evidence reviews 1, 2 and 4)
3. Evidence on the barriers to, and motivators for, behaviour change for specific population groups (such as outdoor workers) was very limited. In particular, it was not clear what sources of information different population groups use. It was also unclear how information about skin cancer influences the way different groups protect themselves from the sun and what motivates them to change their behaviour. (Source: Evidence reviews 3 and 5.)
4. There was a lack of evidence on the specific components of an intervention that make it effective or cost effective. For example, few studies answered questions such as, 'Does effectiveness depend on the intervener?', 'Does the intensity or duration influence effectiveness or duration of effect?' or 'Which component of the intervention had an effect or most effect?' (Source: Evidence reviews 1, 2 and 4.)
5. Routine data collection (for example, on the overall incidence of non‑melanoma skin cancer and on skin cancer rates for different population groups) was not standardised, recorded or made accessible for research. (Source: Expert paper 6.)
6. There was little evidence on which factors help or hinder the provision or use of skin protection resources according to someone's socioeconomic status and ethnicity. (Source: Evidence reviews 3 and 5.)
7. There was no evidence on how interventions to prevent skin cancer affect vitamin D or physical activity levels – generally or for different population groups.
8. No evidence was identified relating to the involvement of private sector organisations (such as sunscreen manufacturers) in the design or delivery of information campaigns and interventions. (Source: evidence reviews 1–5.)
9. There was no evidence on the potential effectiveness of product placement (a form of advertisement where branded goods are placed within television programmes). In particular, there was no evidence to determine if this might be a useful way to communicate sun protection messages to specific at‑risk groups. (At‑risk groups include young people and outdoor workers. (Source: evidence reviews 1, 2 and 4.)
The Committee made four recommendations for research. These are listed in section 5.