Biking at CArnegie Mellon University: Studying the interaction between cyclists and Pedestrians on Campus

OverVIEW 

Much of the design process is accomplished by teams rather than individuals. During design, there often arise situations in which members of a team have different opinions, yet a group decision must still be made. Unfortunately, Arrow's Impossibility Theorem indicates that there is no method for aggregating group preferences that will always satisfy a small number of "fair" conditions.  This project combines empirically collected data with simulated data to test multiple voting strategies and determine which method is most suitable to engineering design scenarios. 

Time: 1 year

Format: Academic Research Project with Chris McComb (PhD Candidate, MechE @ CMU) and Dr. Jonathan Cagan.

Role: Co-Lead Investigator, experimental design, stimuli design, data collection and analysis.

Output: International Conference on Engineering Design, Milan 2015 (Presentation and Peer Reviewed Paper), Journal of Mechanical Design Paper (In Review)

Approach

In this project we examined which voting rules were more likely to lead to outcomes that satisfied Arrow's conditions during the early stages of design. To do this, we first used experiential conjoint methodology to query real preferences for a set of 3D printed mugs. Experiential conjoint allows for the decomposition of a product into a set of discrete or continuous attributes -- in this example various aesthetic features of the drinking mugs were used-- that are combined into different profiles, that participants rate, rank, or choose between.  A multivariate Gaussian distribution of preference weights was created using the empirically collected preference data. These weights were then used to construct, simulate, and analyze thousands of voting scenarios with different numbers of alternatives and voters, and several different voting rules.

Results

Results indicated that the Copeland voting rule (shown above) offered the highest probability of satisfying all of Arrow's conditions. In addition, the Copeland rule was the most strategyproof (most resistant to manipulation by a dishonest individual). A comparison of the results for different voting rules is shown below.