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 |