Page 134 - IJPS-11-3

International Journal of
Population Studies Drivers of reproductive delay in the UK

people trade off more of one attribute for less of another matrix of choice sets large enough to force participants to
(Cleland et al., 2018; Louviere et al., 2010). An attribute make trade-offs between the attributes while also being
is a component that contributes to making a decision: it few enough to not be overly cognitively burdensome or
is a variable such as financial security, partnership status, time-consuming. The D-efficient design also minimizes
and employment status. Each attribute has levels which the standard errors of the parameter estimates produced
can be either qualitative, such as partnership status with from a limited number of choice sets (Rose & Bliemer,
levels that might be “single,” “married,” “cohabiting,” or 2009). In this study, the DCE was made up of 16 choice
quantitative, such as salary or price, but in this case, it is the sets. The nature of the design and the presentation of the
timing of the baby’s arrival in months. This continuous- DCE instrument means that people make choices quite
level attribute can be divided into discrete components quickly and more intuitively than they do when answering
for presentation in the DCE instrument and then used to direct questions (Hensher, 2014). By doing so, they reveal
calculate an estimate of willingness to pay for each attribute. their actual preferences rather than overthinking the
The underlying assumption is that individuals make answers or being otherwise influenced, as may be the case
choices based on the attributes that make up the “product,” when completing regular surveys. Statistical analysis of
in a way that maximizes utility, and by making trade-offs the resulting choices reveals the underlying preferences of
between the attributes (Kjaer et al., 2006). In the application individuals, or their “utility function;” their value beyond
of a DCE, individuals are asked to make a series of choices their cost.
between alternative hypothetical scenarios (called choice
sets); with each choice set being made up of a number of 2.2. Willingness-to-pay
attributes that are split into levels. Table 1 shows an example DCEs typically model a price or salary variable to measure
of a choice set as it looked when presented in the online the maximum amount a consumer is willing to pay (WTP)
DCE for this study. Before choosing from each choice set, for a product feature or how much a potential worker
participants are given qualitative information about what values characteristics of a job as measured in salary, that is,
each attribute means. It is impossible to ask participants how much they would need to be paid to take up the job.
to make choices from a fully-factorial design where all In this study, WTP was modeled as the maximum amount
possible choices are presented as this would mean, for of time, in months, an individual is willing to forgo to have
example, for a DCE with five attributes of three levels each,
245 possible choices would be generated (i.e., 3 ). Instead, their needs met before having a baby. This can also be
5
a D-efficient experimental design is applied, producing a interpreted as the time that can potentially be recuperated
if the barriers to reproduction were lifted.
Table 1. An example of a choice set, presented as part of a 2.3. Data
battery of 16, to university-educated women in the UK study
The successful design of the DCE depends on the quality
Scenario A Scenario B and relevance of available data on the experiment attributes,
Partner support My partner is fully involved My partner is in this case, the barriers to reproduction. In the UK, there
and happy to share the supportive but not are no recent data on this and so we conducted a series of
childcare 50/50. very hands-on with focus groups to learn what people in the UK currently feel
childcare. is preventing them from attaining their fertility goals. The
Career costs I’ve just started a new job My career is well- focus groups generated a rich corpus of qualitative data
which is promising but will established and I am
take some time to establish supported at work. from men and women, aged 23 – 43, university-educated
myself. and not, producing the most current and nuanced data on
Friends My closest friends are all My friends are not what the barriers in the UK currently are. The qualitative
planning babies right now. very baby-oriented leg of this study is described fully elsewhere (Brough &
and many don’t want Sheppard, 2022). A thematic analysis was applied to the
kids. focus group data and the results were used to construct a
Finances The household finances are The household shortlist of four primary barriers (i.e., the DCE attributes)
secure and I have enough finances are a bit for each demographic group (men, women, university, or
savings. stretched and there is
no savings buffer. not) with which to design the experimental instruments.
Baby timing The baby will be born 18 The baby will be born Each group expressed different priorities and so there was
months from now. 3 years from now. a different DCE for each group.
Which scenario is The DCEs were administered by SurveyEngine (a
better? multinational company), a company that specializes in

Volume 11 Issue 3 (2025) 128 https://doi.org/10.36922/ijps.3600