The purpose of this study was to calculate the return on investment (ROI) for Wexham Park Hospital library’s out-of-hours access service, using the contingent valuation (CV) method. The primary objective was to develop and implement a CV survey to elicit library users’ willingness-to-pay (WTP) for out-of-hours access to the library for one year, and secondary objectives of the study were: to use the aggregated WTP value as part of a cost-benefit analysis and ROI calculation; and to evaluate the reliability and validity of the CV method in the context of NHS library services.
A literature review was carried out, followed by a series of semi-structured stakeholder interviews to provide contextual information for the ROI calculation. An online CV survey was designed and distributed to 305 library users who had recently borrowed an access card. The survey used the payment card method to elicit WTP.
The CV survey response rate was 15.49%, and the sample mean WTP value was £5.64 per person, with a 95% confidence interval of £3.47 to £7.99. Regression analysis was carried out on the data to test for validity, but while some coefficients suggest that relationships might exist between some variables and WTP, such as pay band, they were not statistically significant at p<0.05 and the null hypothesis that there was no correlation could not be rejected.
Nevertheless, an aggregated WTP amount was calculated for the year, and used to establish an overall ROI of 4.75 % for the out-of-hours service over the three-year period since implementation.
The study concludes that the CV method is a complex but viable technique for evaluating NHS libraries and that ROI has a key role in the overall evaluation framework for libraries, alongside impact on national targets, patient care and educational outcomes