An archival analysis of sexual assault victims’ age estimation accuracy when describing stranger offenders

Abstract

Approximately 10% of all serious sexual assaults in England and Wales involve victims and offenders who are strangers. The victims often estimate the stranger offender's age during police interviews. These age estimations, if accurate, can help identify offenders. This archival analysis examined the accuracy of 546 stranger sexual assault victims' age estimations. It also examined whether their accuracy can be predicted by victim ageoffender age differences, victim age -offender estimated age differences, victim raceoffender race differences, victim intoxication, victims' duration of exposure to offenders, the time delay between assaults and age estimations, whether offenders have weapons, and whether offenders use sighting precautions. Amongst the descriptive findings, we found victims' mean age estimation error was 4.78 years, the degree of over-and underestimation was equivalent, that only 12.5% of age estimations were within 0.99 years of an offender's true age, but 90% were within 9.99 years of an offender's true age. Only victim ageoffender age differences and, importantly, victim age -offender estimated age differences predicted age estimation accuracy: as age differences decreased, accuracy increased. These findings can help predict stranger sexual assault victims' age estimation accuracy in future cases.

How old was he? Disguises, age, and race impact upon age estimation accuracy

“…However, Amilon et al (2007) asked participants to estimate the age of strangers in a video where face and voice information were both available and the MAE was comparable to the no‐disguise conditions in the current experiments. Similarly, Thorley et al (2018) found sexual assault victims were able to estimate the age of stranger offenders during police interviews with an MAE comparable to the no‐disguise conditions in the current experiments. It is therefore possible that the current findings may replicate if participants estimated the age of 'live' strangers who were wearing sunglasses and/or a hat.…”

“…Experiment 1 replicated earlier findings showing young adults are better at estimating the age of strangers from their own age group and that their accuracy declines as the strangers' chronological ages increase (Anastasi & Rhodes, 2006; George & Hole, 1995; Klugman, 1947; Moyse & Brédart, 2012; Short et al, 2019; Thorley et al, 2018; Voelkle et al, 2012). Here, effect size measures showed the effect of a stranger's age on accuracy was large and, in everyday terms, the young adult participants’ inaccuracy doubled from an average of 5.25 years when strangers were in their twenties to an average of 10.89 years when strangers were in their eighties.…”

“…For example, Voelkle, Ebner, Lindenberger, and Riediger (2012) had young adults estimate the age of 19-80-year-olds and found the average MAE was 5.91 years. Similar averages have been found when participants estimate the age of strangers in videos (Amilon, Weijer, & Schötz, 2007) and when sexual assault victims estimate the age of stranger offenders during police interviews (Thorley, Almond, Gregory, McAlonan, & McLoughlin, 2018).…”

“…If an eyewitness's age estimation is highly inaccurate, innocent people who are younger or older than the offender could be investigated, wasting police resources. Stranger offenders can, of course, come from any age group or race and some will deliberately try to disguise their appearance with sunglasses and a hat (Thorley et al, 2018; van Koppen & Lochun, 1997). The own‐age estimation advantage observed here has been found to occur when eyewitnesses estimate the age of stranger offenders, meaning their estimations are less accurate as the strangers' chronological age increases (Thomas et al, 2004; Thorley et al, 2018).…”

“…Stranger offenders can, of course, come from any age group or race and some will deliberately try to disguise their appearance with sunglasses and a hat (Thorley et al, 2018; van Koppen & Lochun, 1997). The own‐age estimation advantage observed here has been found to occur when eyewitnesses estimate the age of stranger offenders, meaning their estimations are less accurate as the strangers' chronological age increases (Thomas et al, 2004; Thorley et al, 2018). The present experiments suggest age estimation accuracy may decrease further if the eyewitness is White/the offender is Black and the offender was wearing sunglasses.…”