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Updated: Jul 25, 2025
Measuring Delay Discounting in Humans Using an Adjusting Amount Task
Published on: January 9, 2016
Delay Discounting for HIV/STI Testing
Val Wongsomboon1, Gregory D Webster2
1Institute for Sexual and Gender Minority Health and Wellbeing, Northwestern University, 625 N Michigan Ave., Chicago, IL USA.
Insights
Healthcare wait times significantly reduce HIV/STI testing likelihood. People are less likely to get tested for sexually transmitted infections (STIs) the longer they have to wait, especially for milder ones.
Area of Science:
- Behavioral Economics
- Public Health
- Infectious Disease Prevention
Background:
- Wait times in healthcare represent a significant barrier to timely Human Immunodeficiency Virus (HIV) and sexually transmitted infection (STI) testing.
- Understanding factors influencing testing decisions is crucial for effective public health interventions.
Purpose of the Study:
- To examine the impact of delay (wait time) on the likelihood of undergoing HIV/STI testing using a delay discounting approach.
- To investigate whether perceived severity mediates the effect of delay on STI testing decisions.
Main Methods:
- Two studies (N=421, N=392) employed delay discounting tasks where participants reported likelihood of testing based on varied wait times.
- Participants were assigned to chlamydia/gonorrhea or HIV testing groups.
- Study 2 introduced a smaller, sooner outcome (consultation without testing) to explore mediation by perceived severity.
Main Results:
- A systematic reduction in testing likelihood was observed as a function of increased delay to testing, demonstrating delay discounting for HIV/STI tests.
- The effect of delay on testing decisions was more pronounced for chlamydia/gonorrhea testing compared to HIV testing.
- Perceived severity of the STIs statistically mediated the observed discounting effect.
Conclusions:
- Evidence supports delay discounting for HIV/STI testing, with decisions being more sensitive to delays for less severe infections.
- Reducing healthcare wait times, particularly for milder STIs, is essential to mitigate potential serious health consequences from untreated infections.
Introduction:
Wait time in healthcare is an important barrier to HIV/STI testing. Using a delay discounting approach, the current study examined a systematic reduction in testing likelihood as a function of delay (wait time) until testing.
Methods:
In Study 1 (N = 421; data collected in 2019), participants were randomly assigned to either a chlamydia/gonorrhea group or HIV group. A delay discounting task asked them to report how likely they would get tested for the assigned STI if they had to wait for the test (the delay durations varied within persons). In Study 2 (N = 392; data collected in 2020), we added a smaller, sooner outcome (consultation without testing) and tested whether the effect of delay was mediated by perceived severity of the STIs.
Results:
In both studies, the subjective value of a delayed STI test was discounted. That is, people were less likely to undergo STI testing as the delay to STI testing increased. The chlamydia/gonorrhea group discounted delayed testing more than the HIV group (i.e., the effect of delay on testing decisions was stronger for the former). This effect was statistically mediated by perceived severity.
Conclusions:
We found evidence for delay discounting for HIV/STI testing and that testing decisions were more susceptible to delay when the test was for relatively mild STIs.
Policy Implications:
Even mild STIs can cause serious health damage if left untreated. The findings provide strong argument for policies aimed to reduce wait times in healthcare, especially for relatively mild STIs.
