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Table 1 Missing data by country, and how it was handled in imputation models

From: Multiple imputation of multiple multi-item scales when a full imputation model is infeasible

Variables % incomplete (for scale variables, % of missing responses to scale items, not scale totals) Imputed as Used in imputation models as
Austria Belgium England Germany Greece Hungary Netherlands Poland Wales
Total N 323 180 323 274 289 323 237 323 323   
Gender 0 0 0 0 0 0 0 0 0 1 binary item Single item
Age 0 0 0 0 0 0 0 0 0 1 continuous item Single item
Education 3 0 1 0 2 1 0 0 0 1 categorical item Single item
Marital status 2 0 0 1 1 1 0 1 0 1 binary item Single item
Employment 2 0 0 1 1 1 0 2 0 1 binary item Single item
Number of            
 Medical conditions 1 3 0 1 1 0 0 3 0 1 continuous item Single item
 Medicines 1 1 0 2 1 1 2 6 1 1 continuous item Single item
 Tablets 3 3 1 3 1 1 3 12 1 1 continuous item Single item
 Items prescribed 9 6 3 3 1 8 7 26 6 1 continuous item Single item
Dosage frequency 1 2 0 0 1 0 1 0 0 1 ordered categorical item Single item
Morisky adherence 0 0 0 0 0 0 0 0 0 4 binary items Binary item
Medication adherence rating scale 2 3 1 2 1 2 1 4 0 5 ordinal items Scale
Prescription payment 1 2 0 1 1 1 * 1 * 1 categorical item Single item
Affordability problem 1 3 2 1 1 3 1 0 * 1 binary item Single item
Cost coping strategies 2 7 8 3 2 1 * 8 * 6 ordered categorical items 6 single items
Income
 Source 11 23 22 28 12 8 37 46 15 1 categorical item Single item
 Perception 8 25 20 28 12 7 37 46 14 2 items: ordered categorical item conditional on binary item 2 items
 Ease of borrowing 9 23 20 28 12 7 38 48 14 2 items: ordered categorical item conditional on binary item 2 items
 Total 9 24 21 28 12 6 38 46 14 2 items: ordered categorical item conditional on binary item 2 items
Health status 1 1 0 0 0 0 1 0 0 1 ordered categorical item Single item
Practitioner
 Type 7 16 17 23 6 7 29 32 10 1 categorical item Single item
 Gender 10 17 18 22 14 6 29 38 12 1 binary item Single item
Satisfaction with  
 Practitioner 11 18 18 28 2 3 30 35 7 17 ordered categorical items Scale
 Practice 11 23 18 23 6 3 30 34 11 6 ordered categorical items Scale
Optimism 6 15 16 20 5 2 26 26 10 6 ordered categorical items Scale
Illness perception questionnaire: analysed as 8 individual items 9 19 19 25 7 4 31 37 11 8 ordered categorical items Scale
Necessities 6 15 16 20 5 2 27 27 10 5 ordered categorical items Scale
Medicine concerns 6 15 16 20 5 2 27 27 10 6 ordered categorical items Scale
Attitude 9 17 16 24 7 4 30 35 10 7 ordered categorical items Scale
Barriers (theory of planned behaviour) 10 17 16 23 7 3 30 33 11 1 ordered categorical item Single item
Facilitators 11 18 16 24 8 5 30 34 11 3 ordered categorical items Scale
Intention 10 18 17 24 8 4 30 33 10 2 ordered categorical items Scale
Self efficacy 7 1 16 23 6 3 30 31 10 2 ordered categorical items Scale
Normative beliefs 10 20 17 24 7 4 30 33 11 3 ordered categorical items Scale
Barriers 21 22 22 38 18 6 35 35 9 15 ordered categorical items Scale
Social support 10 19 19 23 20 4 31 43 11 7 ordered categorical items Scale
Time preference 14 25 23 23 7 21 32 34 19 4 ordered categorical items 4 single items
Discrete choice experiment: not included in analysis 2 5 7 6 2 1 7 12 2 9 binary items 9 single items
  1. Unless stated, variables correspond to a single predictor during analysis. Due to differences in healthcare and prescription systems between countries, not all questions applied to each country. Additionally, in Wales, one question from the barriers scale was not applicable, thus this scale has only 14 items. Whilst illness perception questions were imputed as scale items, they were analysed individually
  2. * Variables not analysed due to differences in prescription policies