Searching for and classifying non-randomized studies

Workshop category: 

  • Searching and information retrieval
Date and Location

Date: 

Monday 17 September 2018 - 11:00 to 12:30

Location: 

Harris 2
Contact persons and facilitators

Contact person:

Elke Hausner

Facilitators:

Hausner E1, Metzendorf M2, Richter B2
1 Institute for Quality and Efficiency in Healthcare (IQWiG), Germany
2 Metabolic and Endocrine Disorders Group, Germany
Target audience

Target audience: 

Information Specialists

Level of difficulty: 

Intermediate
Type of workshop

Type of workshop : 

Training
Abstract

Abstract:

Background:
Non-randomized studies (NRS) include a wide range of study types (e.g. controlled clinical trial, before-after study, cohort study). These studies may be difficult to identify in the literature, as “study design labels are not used consistently by authors and are not indexed reliably by bibliographic databases” [1].

Objectives:
Our aim is to provide information specialists with:
1) an overview of study designs and guidance on how to classify non-randomized studies;
2) practical examples of abstracts of NRS included in Cochrane Reviews, which are difficult to classify;
3) an overview of search methods for NRS, with a focus on search filters.

Description:
Systematic reviews aim to synthesize the relevant literature as the basis for decision making. In many cases, evidence from NRS might need to be included.
1) We will provide an overview of existing study designs and guidance on how they are reported in abstracts of journal articles. The participants, who will be divided into small groups, will be given a classification exercise. The results will then be compiled and potential challenges discussed.
2) The participants will be given abstracts of NRS included in Cochrane Reviews, which were especially difficult to classify into NRS designs by Cochrane authors. The abstracts will be semantically scrutinized and discussed regarding their possible study design.
3) When searching bibliographic databases for NRS on interventions, it is usually necessary to decide whether existing search filters can be used to search for NRS. For this purpose, the results of a recent validation study of search filters will be presented. Search filter selection and evaluation, as well as alternative search techniques, will be discussed.

References:
1) Reeves BC, Deeks JJ, Higgins JP, Wells GA. Chapter 13: Including non-randomized studies [online]. In: Higgins JP, Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0. (updated March 2011). The Cochrane Collaboration, 2011. Available from handbook.cochrane.org

Relevance to patients and consumers: 

This workshop does not have a direct impact on patients and consumers, as it is of methodological nature. Nonetheless, a better identification of non-randomized studies in bibliographic databases, will allow for better usage of studies that have already been conducted. Thus research waste is avoided, which is a core interest of all patients and consumers.