Adaptation paradigms highlight the dynamic nature of face coding and suggest that identity is coded relative to an average face that is tuned by experience. In low-level vision, adaptive coding can enhance sensitivity to differences around the adapted level. We investigated whether sensitivity to differences around the average face is similarly enhanced. Converging evidence from three paradigms showed no enhancement. Discrimination of small interocular spacing differences was not better for faces close to the average (Study 1). Nor was perceived similarity reduced for face pairs close to (spanning) the average (Study 2). On the contrary, these pairs were judged most similar. Maximum likelihood perceptual difference scaling (Studies 3 and 4) confirmed that sensitivity to differences was reduced, not enhanced, around the average. We conclude that adaptive face coding does not enhance discrimination around the average face.

BackgroundEvidence is required on the cost-effectiveness of alternative changes to the blood collection service.Objectives(1) To estimate the cost-effectiveness of alternative minimum interdonation intervals between whole-blood donations. (2) To investigate donors’ frequency of whole-blood donation according to alternative changes to the blood collection service. (3) To estimate the cost-effectiveness of alternative strategies for maintaining the supply of whole blood.MethodsWe undertook a within-trial cost-effectiveness analysis (CEA) of the INTERVAL trial, stated preference (SP) surveys to elicit donor preferences and a CEA of different strategies for blood collection. The strategies considered were reduced minimum intervals between whole-blood donations, introduction of a donor health report and changes to appointment availability and opening times at blood collection venues. The within-trial CEA included 44,863 donors, with men randomly assigned to 12- versus 10- versus 8-week interdonation intervals, and women to 16- versus 14- versus 12-week interdonation intervals. We undertook a SP survey of non-INTERVAL donors (100,000 invitees). We asked donors to state the frequency with which they would be willing to donate blood, according to the service attribute and level. The CEA compared changes to the blood service with current practice by combining the survey estimates with information from the NHS Blood and Transpant database (PULSE) and cost data. The target population was existing whole-blood donors in England, of whom approximately 85% currently donate whole blood at mobile (temporary) blood collection venues, with the remainder donating at static (permanent) blood collection centres. We reported the effects of the alternative strategies on the number of whole-blood donations, costs and cost-effectiveness.ResultsThe reduced donation interval strategies had higher deferral rates caused by low haemoglobin (Hb), but increased frequency of successful donation. For men in the 8- versus 12-week arm of the INTERVAL trial [Di Angelantonio E, Thompson SG, Kaptoge S, Moore C, Walker M, Armitage J,et al.Efficiency and safety of varying the frequency of whole blood donation (INTERVAL): a randomised trial of 45 000 donors.Lancet2017;390:2360–71], the Hb-related deferral rate was 5.7% per session versus 2.6% per session, but the average number of donations over 2 years increased by 1.71 (95% confidence interval 1.60 to 1.80). A total of 25,187 (25%) donors responded to the SP survey. For static donor centres, extending appointment availability to weekday evenings or weekends, or reduced intervals between blood donations, increased stated donation frequency by, on average, 0.5 donations per year. The CEA found that reducing the minimum interval, extending opening times to weekday evenings and extending opening times to weekends in all static donor centres would provide additional whole blood at a cost per additional unit of £10, £23 and £29, respectively, with similar results for donors with high-demand blood types.LimitationsThe study did not consider the long-term rates at which donors will leave the donation register, for example following higher rates of Hb-related deferral.ConclusionsExtending opening hours for blood donation to weekday evenings or weekends for all static donor centres are cost-effective ways of increasing the supply of high-demand blood types.Future workTo monitor the effects of new strategies on long-term donation frequency.FundingThe National Institute for Health Research Health Services and Delivery Research programme.

The collaborative project successfully piloted a generic impact questionnaire that, subject to further validation, should apply to many types of health library and information services.

Purpose – The purpose of this paper is to critically review methods of impact assessment and economic analyses. Design/methodology/approach – Reviews the literature on impact assessment, and examines some case studies of impact assessment in health libraries. Relates satisfaction and dissatisfaction assessment to impact assessment. Identifies recent impact assessment approaches in public and academic libraries, and explores different uses of terminology for impact and outcome. Reviews literature on economic analysis of value, including cost analyses, cost-effectiveness analysis and return on investment (ROI) studies. Findings – Terms for library assessment (outcome, output, impact, value and benefit) vary among different sectors. Impact evaluation should examine initial assumptions of value carefully, and examine possible gaps in the line of argument linking inputs of library services to presumed impacts (positive and negative). More attention to sampling and response rates is required, to avoid problems such as the “warm glow” effect. Qualitative and quantitative evidence should be carefully integrated to tell the impact story. Economic impact can be estimated, but methodology depends on the service aims and sector. Originality/value – Demonstrates that some of the requirements for traditional impact assessment also affect economic analyses and ROI studies.

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