Division on Addictions, Cambridge Health Alliance, Medford, Massachusetts 02155, USA.
J Stud Alcohol Drugs. 2009 Sep;70(5):751-61. doi: 10.15288/jsad.2009.70.751.
Evolving privacy and confidentiality regulations make achieving high completion rates in longitudinal studies challenging. Periodically reviewing the methods researchers use to retain participants throughout the follow-up period is important. We review the effectiveness of methods to maximize completion rates in a 1-year longitudinal study of repeat driving-under-the-influence (DUI) offenders.
During the course of 21 months, we attempted to follow-up with 704 participants of a licensed residential treatment facility for repeat DUI offenders. High rates of lifetime Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, substance-use disorders (97.6%) and nonsubstance- or nongambling-related psychiatric disorders (44.5%) among the sample made tracking participants difficult. To locate participants and complete follow-up interviews, we obtained baseline information, contacted collaterals, sent mailed reminders, searched Internet databases, and gave a monetary incentive for completing study interviews.
We located 608 participants with active telephone numbers (87.4%) and completed interviews with 488 (70.1% of the entire eligible sample and 80.3% of those with active telephone numbers), after an average (SD) of 8.6 (9.1) calls (median = 5.0). Increasing the number of calls continued to yield additional completions at 10, 20, and 30 calls; at approximately 40 telephone calls, the potential return for additional calls did not justify the added effort.
These results suggest that researchers need to (1) employ more than 10 telephone calls to adequately track difficult-to-follow substance-using populations, and (2) prepare for a subsample of participants who might require more extensive contact. These results highlight the importance of using empirical guidelines to plan estimates for the number of contacts needed to achieve an adequate follow-up completion rate.
不断发展的隐私和保密法规使得在纵向研究中实现高完成率具有挑战性。定期审查研究人员在整个随访期间用于保留参与者的方法非常重要。我们回顾了在一项为期 1 年的复发性酒后驾车（DUI）罪犯纵向研究中最大限度提高完成率的方法的有效性。
在 21 个月的过程中，我们试图对 704 名重复 DUI 罪犯持牌住宿治疗设施的参与者进行随访。样本中终生出现的《精神疾病诊断与统计手册》第 4 版物质使用障碍（97.6%）和非物质或非赌博相关精神障碍（44.5%）的高发病率使得跟踪参与者变得困难。为了找到参与者并完成随访访谈，我们获取了基线信息，联系了联系人，发送了邮寄提醒，搜索了互联网数据库，并为完成研究访谈提供了金钱奖励。
我们找到了 608 名有活动电话号码的参与者（87.4%），并在平均（SD）8.6（9.1）次电话（中位数=5.0）后完成了 488 次访谈（整个合格样本的 70.1%和有活动电话号码的 80.3%）。增加电话次数继续产生额外的完成次数，达到 10 次、20 次和 30 次；在大约 40 次电话后，额外电话的潜在回报不值得付出额外的努力。
这些结果表明，研究人员需要（1）使用超过 10 次电话才能充分跟踪难以追踪的使用物质的人群，并且（2）为可能需要更多联系的参与者的亚样本做好准备。这些结果强调了使用经验准则来计划估计完成足够随访所需的联系次数的重要性。
