Table 1 Data collection methods for the summative and formative evaluation
Data collection methods and timepoints | Indicators to be measured | Measurement instruments | Data analysis |
|---|---|---|---|
Summative evaluation (secondary and primary data) | |||
Secondary data: Extract of pseudonymised contract GP billing data according to § 295 SGB V, n = 2114 GPs (n = 1057 GPs each in the intervention and control group) and at full utilisation ≥ 147,980 patients | Primary outcome: Influenza vaccination rate Secondary outcome: Vaccination uptake rate of the vaccinations recommended by the STIKO for patients aged 60 and older (except for influenza) | - | Descriptive statistics, pre-post comparison (intervention/control group), cluster analysis, subgroup analyses |
Primary data: Cross-sectional patient survey in intervention practices (n = 50), pre- and post-implementation (2 x n = 1250 patients), paper & pencil survey | Secondary outcome: Vaccine literacy | Further secondary outcome: HLS19-VAC-DE subscale of the HLS19 instrument (40) | Descriptive statistics, multivariable regression models, multilevel analysis |
Formative evaluation (primary data only) | |||
Cross-sectional patient survey in intervention practices (n = 50), pre- and post-implementation (2 x n = 1250 patients), paper & pencil survey | Attitudes towards vaccination; intention to get vaccinated; knowledge about vaccination; (un)met information needs; vaccination-related interaction between GP practice staff and patients | 5 C instrument (18, 41); vaccination intention item (42); instrument based on the validated scale developed by Zingg & Siegrist (43) to measure knowledge about vaccination; instrument based on CaPts to measure (un)met information needs (44); self-developed items on vaccination-related interaction between GP practice staff and patients | Descriptive statistics, multivariable regression models, multilevel analysis |
Cross-sectional online survey with GPs and medical assistants in intervention practices (n = 2 × 1057) | Experiences with and evaluation of the intervention elements, also in nursing homes and outpatient care, evaluation of changes in the GP-patient interaction; self-reported communication competence of GPs; structural information related to GP practices | Self-developed, best-fit instruments on experience with and assessment of the intervention; Medical Communication Competence Scale (MCCS; (48); self-developed items on structural information related to GP practices | Descriptive statistics, multilevel analysis after linkage with patient survey data, subgroup analyses |
Qualitative interviews with patients in intervention GP practices, n = 30 | Experiences with the intervention, subjective effectiveness | Semi-structured guideline | Structuring qualitative content analysis according to Kuckartz (49) |
Qualitative interviews with GPs/medical assistants in intervention GP practices, n = 40 | Experiences with the intervention, subjective effectiveness | Semi-structured guideline | Structuring qualitative content analysis according to Kuckartz (49) |