Analyzing Crowd Rankings

Ranked data is ubiquitous in real-world applications, arising naturally when users express preferences about products and services, when voters cast ballots in elections, and when funding proposals are evaluated based on their merits or university departments based on their reputation. This paper focuses on crowdsourcing and novel analysis of ranked data. We describe the design of a data collection task in which Amazon MT workers were asked to rank movies. We present results of data analysis, correlating our ranked dataset with IMDb, where movies are rated on a discrete scale rather than ranked. We develop an intuitive measure of worker quality appropriate for this task, where no gold standard answer exists. We propose a model of local structure in ranked datasets, reflecting that subsets of the workers agree in their ranking over subsets of the items, develop a data mining algorithm that identifies such structure, and evaluate in on our dataset. Our dataset is publicly available at https://github.com/stoyanovich/CrowdRank.