BackgroundThe third sector is becoming a growing provider of public, social, and health services. However, there is little evidence on the effectiveness of third sector organisations (TSOs), and their capacity to implement evidence-based interventions (EBIs). Understanding implementation aspects of service delivery remains an important issue in clinical practice, but is poorly understood in the context of TSOs. This is problematic, since implementation issues are known to be critical for effective intervention outcomes.ObjectivesTo identify and synthesise existing research on what barriers and facilitators influence the implementation process of TSOs delivering EBIs.MethodsThis review is reported according to PRISMA guidelines and was pre-registered in PROSPERO. Key databases were searched using relevant terms, experts in the field were contacted, and websites were reviewed. All identified studies were double-screened, and data were extracted independently by two authors. Included studies were synthesised using thematic analysis and were quality appraised.ResultsThirty-one studies were included, most of which were conducted in North America. The thematic synthesis identified resource limitations, in particular staff and finance, to be the most reported barrier to TSOs implementing EBIs. Organisational culture, including factors such as alignment between the mission of the TSO and EBI, and support/prioritisation of the implementation process were the most reported facilitators. These findings generalise across the included studies and are robust to study quality assessment.ConclusionsWhile it is often assumed that good outcomes follow when implementing interventions that have been developed and tested according to best practice, little attention has been paid to how EBIs are best transported, contextualised, and implemented by third sector providers. This systematic review found that TSOs faced considerable challenges in implementing EBIs, which were primarily a lack of support and expertise, and unclear/insufficient guidelines on how to adapt EBIs to different populations. To address these challenges, it is important to engage with central stakeholders, such as funders, researchers, policymakers, and practitioners, to discuss how these needs can be met.Trial registrationPROSPERO: CRD42017073090.Electronic supplementary materialThe online version of this article (10.1186/s13012-018-0789-7) contains supplementary material, which is available to authorized users.

March 2021protocol via Twitter in order to crowd-source additional relevant studies not identified through the search. All titles and abstracts identified in our search were double-screened using the Rayyan online application. Fourth, to ensure that our analysis is comprehensive in terms of recent and relevant research, on February 14, 2022, and on August 8, 2022, we conducted two comprehensive forward and backward citation searches of all eligible studies identified in the above steps. As noted above, in order to be included in our research sample, estimates of learning progress had to be based on test score measures that could be standardized across studies using Cohen's d.From the studies that meet our inclusion criteria we extracted all estimates of learning progress of school-aged children during the COVID-19 pandemic, separately for math and reading and for different school grades. We also extract the corresponding sample size, standard error, date(s) of measurement, author name(s), and country. Last, we recorded whether studies differentiate between children's socio-economic background, which measure is used to this end, and whether studies find an increase, decrease or no change in learning inequality. We contacted study authors, if any of the information was missing in the study. Data extraction was performed by the first author and validated independently by the second author, with discrepancies resolved through discussion and by conferring with the third author. All extracted information was manually compiled in a spreadsheet using Microsoft Excel (v.16.66.1) and then imported into the statistical program Stata (v.17.0) for our analyses. TimingOur data collection started on April 27, 2021 and ended on August 8, 2022. Data exclusionsStudies were included in the systematic review and meta-analysis based on the inclusion criteria described in the pre-registered study protocol (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021249944). The PRISMA flow diagram in the manuscript (Figure 1) shows the number of studies included and excluded in the systematic review and meta-analysis, as well as the reasons for exclusion. Non-participationNo participants were involved in this study. RandomizationRandomization is not applicable to this study, since our systematic review and meta-analysis examines all available estimates of learning progress of school-aged children during the COVID-19 pandemic. Reporting for specific materials, systems and methodsWe require information from authors about some types of materials, experimental systems and methods used in many studies. Here, indicate whether each material, system or method listed is relevant to your study. If you are not sure if a list item applies to your research, read the appropriate section before selecting a response.

BackgroundThe third sector is becoming a more common provider of social and health services, but little is known about how third sector organisations (TSOs) evaluate their activities. Past research has reported that the third sector is under increasing pressure to evaluate its impact and performance by government and other commissioning bodies. However, in responding to this increased pressure to undertake evaluation, research suggests that many TSOs struggle to evaluate their activities following the principles of evidence-based practice (EBP). Yet, there has been no systematic effort to investigate why the third sector is struggling to provide good quality evidence of its effects.MethodsThis systematic review is reported following the PRISMA guidelines. Ten interdisciplinary databases were searched using a search string developed following best practice and in consultation with an information systems expert. Included studies were primary research of any research design investigating barriers to and facilitators of the evaluation process of TSOs as identified by practitioners. All studies were quality appraised, and the results were synthesised as a thematic summary.ResultsTwenty-four studies were included, which mainly investigated TSOs working within health and social services. The thematic summary identified the main barriers for TSOs to undertake evaluation to be related to the (1) lack of financial resources, (2) lack of technical capability and evaluation literacy and (3) challenges around identifying relevant evaluation systems and outcome indicators. Key facilitating factors involved (1) getting the appropriate support, (2) having an organisational culture that supports evaluation and (3) the motivation to be accountable to stakeholders. These findings were robust to study quality.ConclusionsThis review constitutes the first systematic effort to synthesise existing literature on factors supporting and preventing evaluation by TSOs. The prevalence of factors revolving around the lack of support, resources and clarity on appropriate outcome indicators suggests that many of the identified challenges may be met by applying evidence-based and stakeholder-inclusive strategies to develop shared evaluation requirements. Future efforts should address the application of EBP as part of the commissioning process of TSOs.Electronic supplementary materialThe online version of this article (10.1186/s13643-018-0681-1) contains supplementary material, which is available to authorized users.