Convergence of real-time and retrospective assessments: A systematic investigation of naturally occurring and experimentally induced intrusions

Background and objectives
Ecological momentary assessment is a popular method for monitoring symptoms in real-time. Especially for fleeting experiences, such as intrusions, real-time assessments may be more accurate than retrospective estimates. However, there are concerns regarding reactivity effects associated with real-time assessments and, conversely, the reliance on bias-prone retrospective assessments in clinical science and practice. In this study we used a between-groups design to examine whether real-time intrusion assessments influence retrospective reports (aim 1). Then, we investigated whether real-time and retrospective assessments systematically differed within individuals (aim 2).

Methods
Over two weeks, 150 non-clinical individuals provided weekly retrospective intrusion assessments, while the majority (n = 102) additionally reported their intrusions in real-time, via smartphones. We examined both naturally occurring intrusions, which individuals experience in their everyday lives, and intrusions related to a standardized stressor (i.e., Trier Social Stress Test), taking place halfway.

Results
Using Bayesian statistics, we found that assessing intrusions in real-time did not convincingly affect retrospective reports, and there was no strong evidence that real-time and retrospective intrusion assessments differed. However, the evidence of absence was inconclusive for some measures. Real-time and retrospectively reported intrusion frequencies and distress were strongly associated with one another.

Limitations
Future research is advised to replicate these findings with larger samples, for other types of stressors, in clinical populations, and over extended assessment periods.

Conclusions
The general agreement between real-time and retrospective assessments of intrusions is encouraging, tentatively suggesting that researchers and clinicians can flexibly select the assessment method that best suits their objectives.