Introduction

This user study is conducted to evaluate different color schemes for identifying clusters in scatter plots. The participant needs to identify the number of clusters in each scatter plot by the color of the data points. In a scatter plot, the data points of a cluster have the same color. Data points with different colors are considered different clusters even if the data points are next to each other or overlapped. Close colors with very little color difference, e.g., colors with low contrast or the same color in different shades, are considered the same color in this user study.

The following scatter plot shows an example of clusters. In rectangles A, B, and C, there are two clusters, separately. The data points are colored in dark blue and blue in rectangle A, and green and blue in rectangle B and C. One cluster in rectangle D where all the data points are colored in blue.

The user study will begin with two example scatter plots and questions. There are forty plots in total, which may take 20 minutes to complete the tasks. The same explanation of clusters in a colored scatter plot are shown on top of each plot.
Note: Some plots may take a few seconds to display.

Thanks for your participation :)