OBJECTIVE Effective practices for eliciting and analyzing children's eyewitness reports rely on accurate conclusions about age differences in how children retain information and respond to memory probes. Binning, which is the practice of categorizing continuous variables into discrete groups, can lower studies' power to detect age differences and, in some situations, produce significant but spurious effects. In this article, we (a) describe a systematic review that estimated the frequency of binning age in child eyewitness studies, (b) analyze real and simulated data to illustrate how binning can distort conclusions about age and covariate effects, and (c) demonstrate best practices for analyzing and reporting age trends. HYPOTHESES We expected that researchers would frequently bin age and that we would replicate the negative consequences of binning in the demonstration data sets. METHOD For the systematic review, we retrieved 58 articles describing child eyewitness studies and determined whether researchers binned age for one randomly selected analysis per article. We then compared alternative ways of analyzing actual and simulated data sets. RESULTS Researchers binned age for 64% of the analyses (88% of analyses involving experimental manipulations vs. 35% of the nonexperimental analyses, φ = .55, p < .01). A significant age trend in the real data example was nonsignificant when age was treated as categorical, and in the simulated data sets we demonstrate how this practice may lead to detecting a spurious effect. CONCLUSIONS Treating age as a continuous variable maximizes power to detect real differences without inflating the frequency of spurious results, thereby ensuring that policies regarding child eyewitnesses reflect developmental changes in children's needs and abilities. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

中文翻译：

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儿童目击者研究人员经常分年龄：分析发展趋势的实践和建议的流行。

目标 引出和分析儿童目击者报告的有效做法依赖于关于儿童如何保留信息和对记忆探测作出反应的年龄差异的准确结论。分箱是将连续变量分类为离散组的做法，可以降低研究检测年龄差异的能力，并且在某些情况下会产生显着但虚假的效果。在本文中，我们 (a) 描述了一项系统评价，该评价估计了儿童目击者研究中分箱年龄的频率，(b) 分析真实和模拟数据以说明分箱如何扭曲关于年龄和协变量效应的结论，以及 (c) 证明分析和报告年龄趋势的最佳实践。假设我们预计研究人员会经常进行分箱，并且我们会在演示数据集中复制分箱的负面后果。方法 对于系统评价，我们检索了 58 篇描述儿童目击者研究的文章，并确定研究人员是否对每篇文章随机选择的一项分析进行了年龄分组。然后，我们比较了分析实际和模拟数据集的替代方法。结果 研究人员对 64% 的分析（88% 的分析涉及实验操作与 35% 的非实验分析，φ = .55，p < .01）进行了分类。当年龄被视为分类时，真实数据示例中的显着年龄趋势是不显着的，并且在模拟数据集中，我们展示了这种做法如何导致检测虚假效应。结论 将年龄视为连续变量可最大限度地检测实际差异，而不会增加虚假结果的频率，从而确保有关儿童目击者的政策反映儿童需求和能力的发展变化。（PsycInfo 数据库记录 (c) 2020 APA，保留所有权利）。