Maelstrom Research guidelines for rigorous retrospective data harmonization.

Background: It is widely accepted and acknowledged that data harmonization is crucial: in its absence, the co-analysis of major tranches of high quality extant data is liable to inefficiency or error. However, despite its widespread practice, no formalized/systematic guidelines exist to ensure high quality retrospective data harmonization. Methods: To better understand real-world harmonization practices and facilitate development of formal guidelines, three interrelated initiatives were undertaken between 2006 and 2015. They included a phone survey with 34 major international research initiatives, a series of workshops with experts, and case studies applying the proposed guidelines. Results: A wide range of projects use retrospective harmonization to support their research activities but even when appropriate approaches are used, the terminologies, procedures, technologies and methods adopted vary markedly. The generic guidelines outlined in this article delineate the essentials required and describe an interdependent step-by-step approach to harmonization: 0) define the research question, objectives and protocol; 1) assemble pre-existing knowledge and select studies; 2) define targeted variables and evaluate harmonization potential; 3) process data; 4) estimate quality of the harmonized dataset(s) generated; and 5) disseminate and preserve final harmonization products. Conclusions: This manuscript provides guidelines aiming to encourage rigorous and effective approaches to harmonization which are comprehensively and transparently documented and straightforward to interpret and implement. This can be seen as a key step towards implementing guiding principles analogous to those that are well recognised as being essential in securing the foundational underpinning of systematic reviews and the meta-analysis of clinical trials.

Plan and operation of Cycle 6 of the National Survey of Family Growth.

OBJECTIVES: This report describes how Cycle 6 of the National Survey of Family Growth (NSFG) was designed, planned, and implemented. The NSFG is a national survey of women and men 15-44 years of age designed to provide national estimates of factors affecting pregnancy and birth rates; men's and women's health; and parenting. Cycle 6, conducted in 2002, was the first time the NSFG included a sample of males. METHODS: The survey used in-person, face-to-face interviews conducted by trained female interviewers. One person per household was interviewed from a national area probability sample in about 120 sample areas, with oversamples of teenagers, African Americans, and Hispanics. The data collection used computer-assisted personal interviewing (CAPI). Separate questionnaires were used for female and male respondents. The last section of the questionnaires used a technique called audio computer-assisted self-interviewing (ACASI). In order to control costs and nonresponse errors, survey managers statistically analyzed results from interviewers' visits to sampled households each day, and used those results to allocate interviewer labor and other resources more efficiently. This management improved response rates and made the sample more representative. RESULTS: Over 12,500 interviews were completed, about 7,600 with females and about 4,900 with males. The response rate was about 80 percent for females and about 78 percent for males. The survey procedures were adapted during the fieldwork to achieve the desired response rates and to control costs.