US line-ups outperform UK line-ups

Abstract

In the USA and the UK, many thousands of police suspects are identified by eyewitnesses every year. Unfortunately, many of those suspects are innocent, which becomes evident when they are exonerated by DNA testing, often after having been imprisoned for years. It is, therefore, imperative to use identification procedures that best enable eyewitnesses to discriminate innocent from guilty suspects. Although police investigators in both countries often administer line-up procedures, the details of how line-ups are presented are quite different and an important direct comparison has yet to be conducted. We investigated whether these two line-up procedures differ in terms of (i) discriminability (using receiver operating characteristic analysis) and (ii) reliability (using confidence–accuracy characteristic analysis). A total of 2249 participants watched a video of a crime and were later tested using either a six-person simultaneous photo line-up procedure (USA) or a nine-person sequential video line-up procedure (UK). US line-up procedure yielded significantly higher discriminability and significantly higher reliability. The results do not pinpoint the reason for the observed difference between the two procedures, but they do suggest that there is much room for improvement with the UK line-up.

Designing police lineups to maximize memory performance.

“…Therefore, we use this approach in all of the experiments in which the lineup sizes were the same across conditions (all except in Experiment 4 where the estimated false IDs were used) (Mickes, 2015;Seale-Carlisle & Mickes, 2016).…”

ROCs in Eyewitness Identification: Instructions versus Confidence Ratings

“…Although several different methods can be used to generate ROC data, only one method has been used thus far in the eyewitness ID literature (e.g., Anderson, Carlson, Carlson, & Gronlund, ; Carlson & Carlson, ; Colloff, Wade, & Strange, ; Dobolyi & Dodson, ; Gronlund et al, ; Flowe, Klatt, & Coloff, ; Flowe, Smith, Karoğlu, Onwuegbusi, & Rai, , ; Humphries & Flowe, ; Key et al, ; Lampinen, Erickson, Moore, & Hittson, ; Mickes, ; Neuschatz et al, ; Seale‐Carlisle & Mickes, ; Smith & Flowe, ; Wetmore, Neuschatz, Gronlund, Key, & Goodsell, ; Wetmore, Neuschatz, Gronlund, Wooten, Goodsell, & Carlson, ). That method makes use of confidence ratings that participants provide when they make an ID from a lineup (for a tutorial, see Gronlund et al, ).…”

Child Witness Expressions of Certainty are Informative

“…Young-, middle-, and late-childhood CAC data, plotted using post-identification confidence judgements on (A) the 5-point cup scale, and (B) a collapsed 3-point cup scale. Bars represent standard errors, estimated using a bootstrap procedure (see Seale-Carlisle &Mickes, 2016). The dashed line indicates chance-level performance at the lowest confidence bin and perfect performance at the highest confidence bin.…”