RLI 288  13 RESEARCH LIBRARY ISSUES: A REPORT FROM ARL, CNI, AND SPARC 2016 Tableau Software Although Excel has its advocates for the analysis of the usage of electronic resources in libraries,18 we used Tableau Software19 for analysis and visualization in the second iteration of MINES at UMass. Tableau Software is a business intelligence software that can be used for data analysis and interactive data visualization. It is increasingly popular in analyzing library usage statistics.20 With Tableau, data results can be monitored in real time. Monitoring the results in real time proved useful because early in the study it was observed that an N of 1:200 was not collecting sufficient data to lead to reliable and valid results. With N at 1:200, 3,477 surveys would have been collected over the year, fewer that the 2009–2010 survey. By adjusting the N to 1:140 at the end of the first quarter roughly 5,035 records were collected. Tableau compared the data collected at the Nth use with the data collected for all use at the proxy server to confirm that the distributions were indeed similar and the sample was a representative sample of the population of all EZproxy use. This validity analysis was done on the frequency distribution of web surveys by hour during the day compared to all EZproxy usage and the frequency of usage by month (see Figures 5a and 5b). As can be seen by inspection, the distributions are almost identical. FIGURE 5A. HOURLY MINES SURVEY AND ALL PROXY TRAFFIC