| They sought all primary data, questionnaires, handbooks and documents related to the researchers' work, much of which was confidential. |
| Over 1,800 individuals from various groups provided input via primary data sources, thus strengthening the level of evidence. |
| The first two methods involve the collection of secondary data, while the latter four deal with the collection of primary data. |
| All patient deaths were reported in the primary data set as fractional units of months. |
| The primary data shall be kept for the necessary time in order to carry out any relevant task and at least for five years. |
| Therefore, appropriate use of administrative data is an important tool for arriving at full coverage in the primary data collection. |
