Estimating productivity costs using the friction cost approach in practice: a systematic review.
BACKGROUND
The choice of the most appropriate approach to valuing productivity loss has received much debate in the literature. The friction cost approach has been proposed as a more appropriate alternative to the human capital approach when valuing productivity loss, although its application remains limited. This study reviews application of the friction cost approach in health economic studies and examines how its use varies in practice across different country settings.


METHODS
A systematic review was performed to identify economic evaluation studies that have estimated productivity costs using the friction cost approach and published in English from 1996 to 2013. A standard template was developed and used to extract information from studies meeting the inclusion criteria.


RESULTS
The search yielded 46 studies from 12 countries. Of these, 28 were from the Netherlands. Thirty-five studies reported the length of friction period used, with only 16 stating explicitly the source of the friction period. Nine studies reported the elasticity correction factor used. The reported friction cost approach methods used to derive productivity costs varied in quality across studies from different countries.


CONCLUSIONS
Few health economic studies have estimated productivity costs using the friction cost approach. The estimation and reporting of productivity costs using this method appears to differ in quality by country. The review reveals gaps and lack of clarity in reporting of methods for friction cost evaluation. Generating reporting guidelines and country-specific parameters for the friction cost approach is recommended if increased application and accuracy of the method is to be realized.
Health Economics Unit, School of Health and Population Sciences, University of Birmingham, Birmingham, B15 2TT, UK. j.kigozi@bham.ac.uk.
Jesse
J
Kigozi
Health Economics Unit, School of Health and Population Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
Sue
S
Jowett
Arthritis Research UK Primary Care Centre, Primary Care Sciences, Keele University, Staffordshire, ST5 5BG, UK.
Martyn
M
Lewis
Health Economics Unit, School of Health and Population Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
Pelham
P
Barton
Health Economics Unit, School of Health and Population Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
Joanna
J
Coast
D017281:Cost of Illness; D003365:Costs and Cost Analysis; D017598:Efficiency, Organizational / Q000191:economics*; D006801:Humans; D017059:Models, Econometric
Economic evaluation; Friction cost approach; Friction period; Presenteeism; Productivity costs; Reduced productivity