BackgroundCross-country differences in dietary behaviours and obesity rates have been previously reported. Consumption of energy-dense snack foods and soft drinks are implicated as contributing to weight gain, however little is known about how the availability of these items within supermarkets varies internationally. This study assessed variations in the display of snack foods and soft drinks within a sample of supermarkets across eight countries.MethodsWithin-store audits were used to evaluate and compare the availability of potato chips (crisps), chocolate, confectionery and soft drinks. Displays measured included shelf length and the proportion of checkouts and end-of-aisle displays containing these products. Audits were conducted in a convenience sample of 170 supermarkets across eight developed nations (Australia, Canada, Denmark, Netherlands, New Zealand, Sweden, United Kingdom (UK), and United States of America (US)).ResultsThe mean total aisle length of snack foods (adjusted for store size) was greatest in supermarkets from the UK (56.4 m) and lowest in New Zealand (21.7 m). When assessed by individual item, the greatest aisle length devoted to chips, chocolate and confectionery was found in UK supermarkets while the greatest aisle length dedicated to soft drinks was in Australian supermarkets. Only stores from the Netherlands (41%) had less than 70% of checkouts featuring displays of snack foods or soft drinks.ConclusionWhilst between-country variations were observed, overall results indicate high levels of snack food and soft drinks displays within supermarkets across the eight countries. Exposure to snack foods is largely unavoidable within supermarkets, increasing the likelihood of purchases and particularly those made impulsively.

BackgroundPublic health interventions can be complicated, complex and context dependent, making the assessment of applicability challenging. Nevertheless, for them to be of use beyond the original study setting, they need to be generalisable to other settings and, crucially, research users need to be able to identify to which contexts it may be applicable. There are many tools with set criteria for assessing generalisability/applicability, yet few seem to be widely used and there is no consensus on which should be used, or when. This methodological study aimed to test these tools to assess how easy they were to use and how useful they appeared to be.MethodsWe identified tools from an existing review and an update of its search. References were screened on pre-specified criteria. Included tools were tested by using them to assess the applicability of a Swedish weight management intervention to the English context. Researcher assessments and reflections on the usability and utility of the tools were gathered using a standard pro-forma.ResultsEleven tools were included. Their length, content, style and time required to complete varied. No tool was considered ideal for assessing applicability. Their limitations included unrealistic criteria (requiring unavailable information), a focus on implementation to the neglect of transferability (i.e. little focus on potential effectiveness in the new setting), overly broad criteria (associated with low reliability), and a lack of an explicit focus on how interventions worked (i.e. their mechanisms of action).ConclusionTools presenting criteria ready to be used may not be the best method for applicability assessments. They are likely to be either too long or incomplete, too focused on differences and fail to address elements that matter for the specific topic of interest. It is time to progress from developing lists of set criteria that are not widely used in the literature, to creating a new approach to applicability assessment. Focusing on mechanisms of action, rather than solely on characteristics, could be a useful approach, and one that remains underutilised in current tools. New approaches to assessing generalisability that evolve away from checklist style assessments need to be developed, tested, reported and discussed.Electronic supplementary materialThe online version of this article (10.1186/s12961-018-0364-3) contains supplementary material, which is available to authorized users.

Generalisability is typically only briefly mentioned in discussion sections of evaluation articles, which are unhelpful in judging whether an intervention could be implemented elsewhere, with similar effects. Several tools to assess generalisability exist, but they are difficult to operationalise and are rarely used. We believe a different approach is needed. Instead of focusing on similarities (or more likely, differences) in generic population and setting characteristics, generalisability assessments should focus on understanding an intervention's mechanism of actionwhy or how an intervention was effective. We believe changes are needed to four types of research. First, outcome evaluations should draw on programme theory. Second, process evaluations should aim to understand interventions' mechanism of action, rather than simply 'what happened'. Third, small scoping studies should be conducted in new settings, to explore how to enact identified mechanisms. Finally, innovative synthesis methods are required, in order to identify mechanisms of action where there is a lack of existing process evaluations.

National Immunisation Technical Advisory Groups (NITAGs) provide independent guidance to health ministries to support evidence-based and nationally relevant immunisation decisions. We examined NITAGs' value, sustainability, and need for support in low and middle-income countries, drawing from a mixed-methods study including 130 global and national-level key informant interviews. NITAGs were particularly valued for providing independent and nationally owned evidence-based decision-making (EBDM), but needed to be integrated within national processes to effectively balance independence and influence. Participants agreed that most NITAGs, being relatively new, would need developmental and strengthening support for at least a decade. While national governments could support NITAG functioning, external support is likely needed for requisite capacity building. This might come from Gavi mechanisms and WHO, but would require alignment among stakeholders to be effective.