Trajectory modelling techniques have been developed to determine subgroups within a given population and are increasingly used to better understand intra- and inter-individual variability in health outcome patterns over time. The objectives of this narrative review are to explore various trajectory modelling approaches useful to epidemiological research and give an overview of their applications and differences. Guidance for reporting on the results of trajectory modelling is also covered. Trajectory modelling techniques reviewed include latent class modelling approaches, ie, growth mixture modelling (GMM), group-based trajectory modelling (GBTM), latent class analysis (LCA), and latent transition analysis (LTA). A parallel is drawn to other individual-centered statistical approaches such as cluster analysis (CA) and sequence analysis (SA). Depending on the research question and type of data, a number of approaches can be used for trajectory modelling of health outcomes measured in longitudinal studies. However, the various terms to designate latent class modelling approaches (GMM, GBTM, LTA, LCA) are used inconsistently and often interchangeably in the available scientific literature. Improved consistency in the terminology and reporting guidelines have the potential to increase researchers’ efficiency when it comes to choosing the most appropriate technique that best suits their research questions.

This paper questions the view that performance-based financing (PBF) in the health sector is an effective, efficient and equitable approach to improving the performance of health systems in low-income and middle-income countries (LMICs). PBF was conceived as an open approach adapted to specific country needs, having the potential to foster system-wide reforms. However, as with many strategies and tools, there is a gap between what was planned and what is actually implemented. This paper argues that PBF as it is currently implemented in many contexts does not satisfy the promises. First, since the start of PBF implementation in LMICs, concerns have been raised on the basis of empirical evidence from different settings and disciplines that indicated the risks, cost and perverse effects. However, PBF implementation was rushed despite insufficient evidence of its effectiveness. Second, there is a lack of domestic ownership of PBF. Considering the amounts of time and money it now absorbs, and the lack of evidence of effectiveness and efficiency, PBF can be characterised as a donor fad. Third, by presenting itself as a comprehensive approach that makes it possible to address all aspects of the health system in any context, PBF monopolises attention and focuses policy dialogue on the short-term results of PBF programmes while diverting attention and resources from broader processes of change and necessary reforms. Too little care is given to system-wide and long-term effects, so that PBF can actually damage health services and systems. This paper ends by proposing entry points for alternative approaches.

Objectives Growing attention has been given to considering sex and gender in health research. However, this remains a challenge in the context of retrospective studies where self-reported gender measures are often unavailable. This study aimed to create and validate a composite gender index using data from the Canadian Community Health Survey (CCHS). Methods According to scientific literature and expert opinion, the GENDER Index was built using several variables available in the CCHS and deemed to be gender-related (e.g., occupation, receiving child support, number of working hours). Among workers aged 18-50 years who had no missing data for our variables of interest (n = 29,470 participants), propensity scores were derived from a logistic regression model that included gender-related variables as covariates and where biological sex served as the dependent variable. Construct validity of propensity scores (GENDER Index scores) were then examined. Results When looking at the distribution of the GENDER Index scores in males and females, they appeared related but partly independent. Differences in the proportion of females appeared between groups categorized according to the GENDER Index scores tertiles (p < 0.0001). Construct validity was also examined through associations between the GENDER Index scores and gender-related variables identified a priori such as choosing/avoiding certain foods because of weight concerns (p < 0.0001), caring for children as the most important thing contributing to stress (p = 0.0309), and ability to handle unexpected/difficult problems (p = 0.0375). Conclusion The GENDER Index could be useful to enhance the capacity of researchers using CCHS data to conduct genderbased analysis among populations of workers. Résumé Objectifs Dans le domaine de la recherche en santé, une attention grandissante est portée à l'importance de tenir compte à la fois du sexe et du genre. Toutefois, ceci représente un défi quand on travaille avec des données existantes qui ne contiennent pas toujours de mesure autoraportée de genre. L'objectif de cette étude était donc de développer et valider un indice composite de genre grâce aux données de l'Enquête sur la santé dans les collectivités canadiennes (ESCC).

Realist reviews are a new form of knowledge synthesis aimed at providing middle-range theories (MRTs) that specify how interventions work, for which populations, and under what circumstances. This approach opens the ‘black box’ of an intervention by showing how it triggers mechanisms in specific contexts to produce outcomes. We conducted a realist review of health user fee exemption policies (UFEPs) in sub-Saharan Africa (SSA). This article presents how we developed both the intervention theory (IT) of UFEPs and a MRT of free public healthcare seeking in SSA, building on Sen’s capability approach. Over the course of this iterative process, we explored theoretical writings on healthcare access, services use, and healthcare seeking behaviour. We also analysed empirical studies on UFEPs and healthcare access in free care contexts. According to the IT, free care at the point of delivery is a resource allowing users to make choices about their use of public healthcare services, choices previously not generally available to them. Users’ ability to choose to seek free care is influenced by structural, local, and individual conversion factors. We tested this IT on 69 empirical studies selected on the basis of their scientific rigor and relevance to the theory. From that analysis, we formulated a MRT on seeking free public healthcare in SSA. It highlights three key mechanisms in users’ choice to seek free public healthcare: trust, risk awareness and acceptability. Contextual elements that influence both users’ ability and choice to seek free care include: availability of and control over resources at the individual level; characteristics of users’ and providers’ communities at the local level; and health system organization, governance and policies at the structural level.