User variance and its impact on video retrieval benchmarking
Wilkins, Peter, Troncy, Raphael, Halvey, Martin, Byrne, DaraghORCID: 0000-0002-2040-9765, Amin, Alia, Punitha, P., Smeaton, Alan F.ORCID: 0000-0003-1028-8389 and Villa, Robert
(2009)
User variance and its impact on video retrieval benchmarking.
In: CIVR 2009 - ACM International Conference on Image and Video Retrieval, 8-10 July, 2009, Santorini, Greece.
ISBN 978-1-60558-480-5
In this paper, we describe one of the largest multi-site interactive video retrieval experiments conducted in a
laboratory setting. Interactive video retrieval performance is difficult to cross-compare as variables exist across
users, interfaces and the underlying retrieval engine. Conducted within the framework of TRECVID 2008, we completed a
multi-site, multi-interface experiment. Three institutes participated involving 36 users, 12 each from Dublin City
University (DCU, Ireland), University of Glasgow (GU, Scotland) and Centrum Wiskunde \& Informatica (CWI, the
Netherlands). Three user interfaces were developed which all used the same search service. Using a latin squares
arrangement, each user completed 12 topics, leading to 6 TRECVID runs per site, 18 in total. This allowed us to isolate
the factors of users and interfaces from retrieval performance. In this paper we present an analysis of both the
quantitative and qualitative data generated from this experiment, demonstrating that for interactive video retrieval
with ``novice'' users, performance can vary by up to 300\% for the same system using different sets of users, whilst
differences in performance of interface variants was in comparison not statistically different. Our results have
implications for the manner in which interactive video retrieval experiments using non-expert users are evaluated. The primary focus of this paper is in highlighting that non-expert users generate very large performance fluctuations, which may either mask or create system variability. The discussion of why this happened is not covered by this paper.