Appendix D: Gaps in the evidence

Appendix D: Gaps in the evidence

The PDG identified a number of gaps in the evidence related to the programmes under examination, based on an assessment of the evidence in the various reviews. These gaps are set out below.

  1. The qualitative literature mainly focuses on school and sport. There is little evidence on formal or informal activities outside school such as yoga, dance, aerobics and play, or activities in social settings. Provision of non-competitive recreational physical activities has rarely been compared with more traditional school sporting activities (in or outside normal school hours). Comparisons between recreational physical activities organised with groups of friends – or with groups of a similar ability – are also lacking.

  2. There is limited evidence about what prevents children and young people from being physically active – or what encourages them. Lack of detail in the intervention descriptions means it is unclear whether the barriers or facilitators identified in the qualitative literature were addressed.

  3. Few studies report on all physical activities that the participant is involved in. Most only report changes in the activity targeted by the intervention. Whether or not one type of physical activity will displace another – and the factors affecting any such displacement – are not identified.

  4. Few studies have investigated the relationship between children's and parents' physical activity over time. There is little evidence about what encourages families to be physically active (either together or split into adult–child groups). There is also little evidence about how families manage competing priorities when planning such activities.

  5. Little is known about how children and young people view travel involving physical activity (such as walking and cycling) and how to promote it to them. The exception relates to journeys to and from school.

  6. There is little evidence on how to sustain 'active' travel initiatives. For example, little is known about how best to recruit and retain walking bus leaders and local champions, or how effective it is to use pedometers to promote walking among children and young people. In addition, the effect of the environment on uptake (that is, urban versus rural settings and flat versus hilly terrain) has not been properly considered.

  7. The intervention literature has methodological limitations. Descriptions of the interventions and evaluation methods used are limited (which may, to some extent, reflect publishing restrictions). In addition, implementation fidelity is rarely assessed and few studies have long-term follow-up. Often studies do not take potential mediator variables into account and do not use objective measures of overall physical activity when measuring effectiveness.

  8. Much of the evidence comes from urban settings and its relevance to children from rural areas needs to be considered.

  9. No studies were identified that measured the use of rewards to increase participation in – and enjoyment of – organised physical activity.

  10. No studies were found which evaluated UK-based, multi-component interventions.

  11. Evidence is scarce on how to encourage groups of children and young people who are least likely to be physically active. They include: those with disabilities (or from families where someone else is disabled), those with special educational needs and those from certain minority ethnic groups or traveller and refugee communities.

  12. There is a lack of evidence on the effectiveness of private or community-based physical activity provision.

  13. There is little evidence of what works to encourage young children to be physically active. For example, the mediating role of parents and practitioners has not been explored. In addition, the evidence about whether or not play initiatives encourage pre-school children to be active is contradictory.

  14. There is virtually no evidence on the cost-effectiveness of interventions to increase children and young people's physical activity levels. Many studies use weak measurements of effectiveness (as noted above). As a result, the opportunities to use modelling methods to estimate cost-effectiveness were limited.

  15. Few longitudinal studies track the relationship between physical activity and health outcomes. Likewise, few interventions have been well-evaluated over the longer term.

The Group made five recommendations for research. These are listed in section 5.

  • National Institute for Health and Care Excellence (NICE)