“…Ten studies [35,44,58,62,64,65,[69][70][71]74] used questionnaires to collect data on absenteeism, ten [33,34,39,42,51,57,60,61,68,92] used literature estimates, three [48][49][50] used estimates provided by medical professionals, one [63] used cost diaries, one [75] used data on doctors' certificates for absenteeism and five [40,41,66,72,73] did not specify the methods used to collect data on lost work time. Regarding the valuation of time lost from work, 13 studies [40,41,60,[62][63][64]66,[70][71][72][73]75,92] applied average (age/ sex dependent) wage and employment rates, five [49][50][51]61,68] used values based on GDP per capita,...…”