Measuring the Eccentricity of Items

TL;DR

This paper introduces a new metric called item eccentricity to distinguish between popular items loved by the general public and niche items favored by eccentric fans, revealing stable and distinct characteristics in real-world datasets.

Contribution

The paper proposes a novel item eccentricity metric that effectively differentiates between eccentric and non-eccentric items, surpassing previous popularity-based measures.

Findings

Eccentricity remains stable over time.

Eccentric and non-eccentric items have distinct characteristics.

The metric successfully separates eccentric items in the tail.

Abstract

The long-tail phenomenon tells us that there are many items in the tail. However, not all tail items are the same. Each item acquires different kinds of users. Some items are loved by the general public, while some items are consumed by eccentric fans. In this paper, we propose a novel metric, item eccentricity, to incorporate this difference between consumers of the items. Eccentric items are defined as items that are consumed by eccentric users. We used this metric to analyze two real-world datasets of music and movies and observed the characteristics of items in terms of eccentricity. The results showed that our defined eccentricity of an item does not change much over time, and classified eccentric and noneccentric items present significantly distinct characteristics. The proposed metric effectively separates the eccentric and noneccentric items mixed in the tail, which could not be done with the previous measures, which only consider the popularity of items.