Beyond Convenience: A Case and Method for Purposive Sampling in Chemistry Teacher Professional Development Research

When designing a study, the sampling method for selecting research participants is an important decision with a host of considerations. When designing a professional development (PD) program with a limited number of spaces, the method of choosing participants from the applicants is also important. When research and professional development are entwined, sets of sampling criteria could conflict. Additionally, in a mixed methods study, such as the one undertaken by the researchers, additional trade-offs exist when considering the many potential methods of sampling and participant selection. In this report, we present a novel solution to the problem of multiple-criterion-focused selection of research and PD participants when the number of applicants to participate outnumbers the availability of resources. By using a weighted ranking system, we were able to incorporate multiple purposive sampling criteria in a simultaneous, rather than sequential, fashion. This allowed us to focus our evaluation of chemistry-specific free-response questions on a narrower pool of finalists and more consistently rate their responses. This multipurposive sampling method and a novel tool developed herein have broad implications for both sampling for chemistry education research and participant selection in professional development.在开展研究设计时，选取研究参与者的抽样方法是一项需综合考量诸多因素的关键决策。当设计名额有限的专业发展（Professional Development, PD）项目时，从申请者中遴选参与者的方法同样至关重要。当研究与专业发展项目相互交织时，多套抽样标准可能产生冲突。此外，在本研究团队所开展的这类混合方法研究中，当权衡诸多潜在的抽样与参与者遴选方案时，还会面临额外的取舍难题。本报告针对申请者人数超出资源承载上限时，研究与专业发展项目参与者的多标准遴选困境，提出了一种全新解决方案。通过采用加权排序系统，我们得以以同步而非逐次的方式整合多项目的性抽样标准。这使得我们能够将化学领域自由作答试题的评估范围限定在更精简的终选候选人群体中，并更一致地对其作答情况进行评分。此种多用途抽样方法，以及本文中开发的全新工具，将对化学教育研究中的抽样工作，以及专业发展项目中的参与者遴选工作，均具有广泛的应用价值与启示意义。