Noone Chris, Southgate Alex, Ashman Alex, Quinn Éle, Comer David, Shrewsbury Duncan, Ashley Florence, Hartland Jo, Paschedag Joanna, Gilmore John, Kennedy Natacha, Woolley Thomas E, Heath Rachel, Goulding Ryan, Simpson Victoria, Kiely Ed, Coll Sibéal, White Margaret, Grijseels D M, Ouafik Maxence, McLamore Quinnehtukqut
School of Psychology, University of Galway, University Road, Galway, H91 TK33, Ireland.
School of Physics & Astronomy, Cardiff University, Cardiff, CF10 3 AT, UK.
BMC Med Res Methodol. 2025 May 10;25(1):128. doi: 10.1186/s12874-025-02581-7.
The Cass Review aimed to provide recommendations for the delivery of services for gender diverse children and young people in England. The final product of this project, the Cass report, relied on commissioned research output, including quantitative and qualitative primary research as well as seven systematic reviews, to inform its recommendations and conclusions.
We critically evaluated the Cass report and the research that was commissioned to inform it. To evaluate the Risk of Bias within the seven systematic reviews commissioned by the Cass Review, we applied the ROBIS tool - a domain-based assessment of risk of bias within systematic reviews. It focuses on four domains (i) study eligibility criteria, (ii) identification and selection of studies, (iii) data collection and study appraisal, and (iv) synthesis and findings. To maintain rigour, the ROBIS tool was applied to each systematic review by two independent assessors, within Covidence, with conflicts resolved by an additional two independent assessors. We also conducted a detailed critical evaluation of the methods used in the survey of gender services for young people in Europe, the two quantitative studies of health records, and the qualitative study on the experience of gender dysphoria among young people and the claims made in the Cass report based on these studies.
Using the ROBIS tool, we identified a high risk of bias in each of the systematic reviews driven by unexplained protocol deviations, ambiguous eligibility criteria, inadequate study identification, and the failure to integrate consideration of these limitations into the conclusions derived from the evidence syntheses. We also identified methodological flaws and unsubstantiated claims in the primary research that suggest a double standard in the quality of evidence produced for the Cass report compared to quality appraisal in the systematic reviews.
We discuss these issues in relation to how evidence regarding gender affirming care is framed, the wider political context, and the future for gender affirming care. The Cass report's recommendations, given its methodological flaws and misrepresentation of evidence, warrant critical scrutiny to ensure ethical and effective support for gender-diverse youth.
卡斯审查旨在为英格兰为性别多元的儿童和年轻人提供服务提出建议。该项目的最终成果《卡斯报告》依赖委托研究产出，包括定量和定性的原始研究以及七项系统评价，以为其建议和结论提供依据。
我们对《卡斯报告》及其委托开展的相关研究进行了严格评估。为评估卡斯审查委托开展的七项系统评价中的偏倚风险，我们应用了ROBIS工具——一种基于领域的系统评价偏倚风险评估工具。它聚焦四个领域：（i）研究纳入标准；（ii）研究的识别与选择；（iii）数据收集与研究评估；（iv）合成与结果。为保持严谨性，两名独立评估人员在Covidence内将ROBIS工具应用于每项系统评价，另外两名独立评估人员解决分歧。我们还对欧洲青少年性别服务调查、两项健康记录定量研究以及青少年性别焦虑症经历的定性研究中使用的方法，以及《卡斯报告》基于这些研究提出的主张进行了详细的严格评估。
使用ROBIS工具，我们发现每项系统评价中均存在较高的偏倚风险，原因包括无法解释的方案偏差、模糊的纳入标准、研究识别不充分以及未能将这些局限性的考虑纳入证据合成得出的结论中。我们还在原始研究中发现了方法学缺陷和未经证实的主张，这表明与系统评价中的质量评估相比，为《卡斯报告》提供的证据质量存在双重标准。
我们结合性别肯定性医疗证据的构建方式、更广泛的政治背景以及性别肯定性医疗的未来来讨论这些问题。鉴于其方法学缺陷和对证据的错误表述，《卡斯报告》的建议值得严格审查，以确保为性别多元的青少年提供符合伦理且有效的支持。
