Items considered during the initial development of a health-related quality of life (HRQoL) instrument.
| Number of items | Single item for single concept |
| Multiple items for a single concept | |
| Multiple items for multiple domains within a concept | |
| Intended measurement | Generic vs specific (condition-specific, population-specific) |
| Data collection method | Interviewer-administered |
| Self-administered | |
| Interactively administered (computer-assisted, web-based interactive voice response) | |
| Timing | As events occur; at defined intervals throughout a study |
| Timeframe: within the last “period” (i.e., within last week, 2 weeks, month, etc.) | |
| Types of scores | Single rating on a single concept |
| Index (single score combining multiple ratings of related domains or individual concepts | |
| Profile (multiple uncombined scores of multiple related domains) | |
| Battery (multiple uncombined scores of independent concepts) | |
| Composite (single rating, index, profile, or battery) | |
| Weighting of items or concepts | All items and domains are equally weighted |
| Items are assigned variable weights | |
| Domains are assigned variable weights | |
| Response formats | Visual analog scale, Likert scale, rating scale, checklist |