Skip to main content

Table 2 Consensus on four main steps in the selection of outcome measurement instruments for Core Outcome Sets (COSs), including their tasks

From: How to select outcome measurement instruments for outcomes included in a “Core Outcome Set” – a practical guideline

  Percentage of agreement in the Delphi study (%)
Step 1. Conceptual considerations
Aspects to consider before starting to search for outcome measurement instruments:
1. The construct (i.e., outcome or domain) to be measured 98
2. The target population (e.g., age, gender, disease characteristics) 99
Step 2. Finding existing outcome measurement instruments
COS developers should aim for finding all existing outcome measurement instruments. 72
When finding outcome measurement instruments, COS developers can have three sources of information: (1) systematic reviews, (2) literature searches, and (3) other sources (optional)  
1. COS developers use existing, good quality, and up-to-date systematic reviews of outcome measurement instruments 94
2 a. MEDLINE (e.g., through the PubMed or OVID interface) is considered the minimum database to consult in finding all existing outcome measurement instruments. An additional search in EMBASE is highly recommended 99 and 82, respectively
b. Reference lists of the included studies should be checked to find all existing outcome measurement instruments 91
3. Additional sources may be considered as optional sources in finding relevant outcome measurement instruments 89
Step 3. Quality assessment of outcome measurement instruments
To evaluate the quality of the outcome measurement instruments, COS developers evaluate (1) the measurement properties and (2) the feasibility aspects of the identified outcome measurement instruments  
1. Evidence on the measurement properties should be available in the target populationa 70–93
2. Feasibility aspects should be taken into consideration in the selection of outcome measurement instruments for outcomes included in a COSb 77–97
Step 4. Generic recommendations on the selection of outcome measurement instruments for a COS
1. Select only one outcome measurement instrument for each outcome (e.g., construct or domain) in a COS 90
2. The minimum requirements for including an outcome measurement instrument in a COS are: at least high quality evidencec for goodd content validity and for goodd internal consistency (if applicable), and if the outcome measurement instrument is feasible 81
3. A consensus procedure to agree on the outcome measurement instruments for each outcome included in a COS should be performed among all relevant stakeholders, including patients 90
  1. aSee Table 3 for the percentage of agreement per measurement property separately
  2. bSee Table 6 for the percentage of agreement per feasibility aspect separately
  3. c“High quality evidence” is defined as consistent findings in multiple studies of at least good quality OR in one study of excellent quality AND a total sample size of 100 patients or more (Table 5)
  4. d“Good” is defined as a “+”  rating according to the criteria for good measurement properties (Table 4)
Back to article page

Trials

ISSN: 1745-6215