COSMIN Risk of Bias tool to assess the quality of studies on reliability or measurement error of outcome measurement instruments: a Delphi study

Table 2 Consensus of components of outcome measurement instruments that do not involve biological sampling

Component	Consensus^a on the term (%)	Elaboration	Consensus on the elaboration (%)
Equipment	43/48 (90%) (R2^b)	All equipment used in preparation, administration, and assigning scores	43/48 (90%) (R2)
Preparatory actions	38/46 (83%) (R2)	1. ‘First time only’ general preparatory actions, such as required expertise or training for professionals to prepare, administer, store or assign the scores 2. Specific preparatory actions for each measurement, such as • preparations of equipment by professionals^c • preparations of the patient^d by the professional • Preparations undertaken by the patients	37/46 (80%) (R2)
Unprocessed data collection	30/44 (68%) (R2)	What the patient and/or professional(s) actually do to obtain the unprocessed data	33/44 (75%) (R2)
Data processing and storage	44/44 (100%) (R2)	All actions undertaken on the unprocessed data to allow the assignment of the score	37/44 (84%) (R2)
Remove: ‘preparation of scoring’	39/44 (89%) (R2)
Assignment of the score	36/44 (82%) (R2)	Methods used to transform processed data into a final score^e on the outcome measurement instrument.	34/44 (77%) (R2)

^a Consensus was set at 67% of the panelists (strongly) agreed to a proposal, the denominator can be decreased because panelists considered themselves to have ‘no expertise’ on a specific proposal or dropped-out; ^b R2: consensus reached in Round 2; ^c Professionals are those who are involved in the preparation or the performance of the measurement, in the data processing, or in the assignment of the score; this may be done by one and the same person, or by different persons; ^d In the COSMIN methodology we use the word ‘patient.’ However, sometimes the target population is not patients, but e.g. healthy individuals, caregivers, clinicians, or body structures (e.g. joints, or lesions). In these cases, the word patient should be read as e.g. healthy volunteer, or clinician; ^e The score can be further used or interpreted by converting a score to another scale, metric or classification. For example, a continuous score is classified into an ordinal score (e.g. mild/moderate/severe), a score is dichotomized into below or above a normal value, patients are classified as responder to the intervention (e.g. when their change is larger than the Minimal Important Change (MIC) value)

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