Accessibility in Information Retrieval

TL;DR

The paper addresses how to quantify document retrievability in an information space by importing the transportation concept of accessibility. It defines a system-dependent measure $A({\bf d}) = \sum_{{\bf q} \in {\bf Q}} o_q \cdot f(c_{dq}, {\theta})$ and instantiates it with two IR-adapted forms: a cumulative variant with a cutoff $c$ and a gravity-based variant with a dampening factor $\beta$, where the distance $c_{dq}$ is rank-based. The authors connect $\beta = 1$ to reciprocal rank and expected search length, and argue that document accessibility can inform design, tuning, and management of IR systems beyond traditional effectiveness or efficiency metrics. They outline future work on calibration, estimation, and practical application of document-accessibility measures to diagnose biases, manage collections, and optimize access patterns.

Abstract

This paper introduces the concept of accessibility from the field of transportation planning and adopts it within the context of Information Retrieval (IR). An analogy is drawn between the fields, which motivates the development of document accessibility measures for IR systems. Considering the accessibility of documents within a collection given an IR System provides a different perspective on the analysis and evaluation of such systems which could be used to inform the design, tuning and management of current and future IR systems.