A STATED CHOICE EXPERIMENT TO INVESTIGATE PREFERENCES FOR INFORMATION PROVISION IN NEWBORN BLOODSPOT SCREENING PROGRAMMES
Method: Following piloting (n=50), an on-line hybrid (linked conjoint analysis (CA) and discrete choice experiment (DCE)) stated choice experiment, was completed by a public sample (recruited via an internet panel provider). Two survey versions (A: NBSP for 9 conditions; B: NBSP for 20 conditions) comprised four tasks each: a validated measure of attitudes towards involvement in decision-making; six CA questions (11 information attributes); ten DCE questions (4 attributes: 3 process and the ability to make an informed decision); demographic questions. Literature reviews and 13 semi-structured interviews informed attribute/level selection. The design criteria were orthogonal foldover arrays (CA) and Bayesian D-efficiency using Ngene (DCE). The CA and DCE data were analysed separately and then linked using ordered logit and logit models. Marginal willingness-to-pay (WTP) values with 95% confidence intervals (CI) were calculated.
Result: The sample comprised 700 respondents (58% female; mode age band 25 to 34 years; 48% with university degree: 48% parents). A high proportion (37%) of respondents indicated wanting to make decisions about screening after the midwife provided information and a recommendation. Responses differed between versions A and B. In version A, respondents positively valued: all information attributes except the possibility of receiving false-positive results or how parents can prepare their baby; information early in pregnancy (WTP £14.32; CI: £8.25 to £21.43); receiving information in an individual discussion (WTP £10.57; CI: £5.84 to £16.44); the ability to make a decision about screening (WTP £13.51; CI: £10.72 to £16.52).
In version B, respondents positively valued: all information attributes (CA); information early in pregnancy (WTP £15.20; CI: £7.72 to £23.68); the ability to make a decision about screening (WTP £16.05; CI: £12.28 to £20.82). Respondents completing version B had no significant preferences for how information is given.
Conclusion: This hybrid CA-DCE was able to elicit preferences for information provision in the context of a NBSP. Respondents stated a need for different types of information to allow them to make an informed decision and had clear preferences about which information was more important and what format of information provision was preferred, which was in some instances affected by the number of conditions included in the NBSP.