Skip to main content

Early identification of substandard breast screening performers


All UK breast screeners can voluntarily undertake the PERFORMS scheme, where they examine recent screening cases receiving immediate feedback. Once all individuals have participated, data are calculated on how they performed compared with peers allowing poor performers to be identified. A way of potentially identifying such poor performers much earlier is proposed.


Information from the last round of the PERFORMS scheme was reanalysed for which the low performance threshold value was known. Data for randomly selected small groups of participants were repeatedly bootstrapped with the aim of artificially determining a threshold of low performance and comparing this with the known actual threshold. Using a varying number from four to 50 participants, a sample of 1,000 randomly selected small groups was constructed for each number of participants. After bootstrapping each small group, a distribution of 1,000 thresholds of low performance was constructed and median values and standard errors of this distribution calculated to determine how the number of participants affected the estimation accuracy.


The standard error of the estimated threshold reduced as group size increased, indicating better estimation accuracy. Using data from as few as 10 people the artificial threshold approached the known actual threshold of poor performance.


Individuals who are performing less than their peers on the scheme can be identified early without all screeners having first taken part. Whilst not an absolute outlier measure, this information can be fed back in a timely manner, so enabling the individual to improve their cancer identification performance.

Author information

Authors and Affiliations


Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article

Dong, L., Chen, Y. & Gale, A. Early identification of substandard breast screening performers. Breast Cancer Res 13 (Suppl 1), P13 (2011).

Download citation

  • Published:

  • DOI: