This week we review Chapter 4 in our textbook, Effective Data Visualization, which goes over the importance of including a benchmark in our visuals. Benchmarks are extremely important because without that context, we limit the amount of information we can pull from a graph. Adding benchmark information clearly displays what the data is being compared to. This simple detail allows the viewer to easily determine whether performance was good, bad, or close to the mark.

This graph from The New York Times shows the monthly global temperature compared with preindustrial levels. The benchmark on this graph is the data for the year 2023, and the other years since 1940 are what is being compared to the benchmark. Just by quickly looking at this visual we can tell that global temperatures were much lower in previous years than in 2023. This benchmark stands out because the line is a darker color and much bolder than all of the others. This visualization is highly effective because the years prior to 2023 are a lighter opacity and color. The creator also only included data labels for the points in 2023.

Another graph from The New York Times displays the daily average sea surface temperatures. This visualization also includes a benchmark to help viewers easily process the data being shown. The gray dotted line, representing the average temperatures from 1991-2020, is the benchmark in this data. The blue line is the most current information which is being compared to the benchmark. In this graph we see that the temperatures in 2023 are much higher than the average between 1991-2020.

Lastly, this graph of Antarctica’s sea ice mass shows that levels in 2023 are much lower than the average from 1979-2010. The gray dotted line is the benchmark, while the red line is the data being compared. While this visualization is still effective, I believe the previous two were better. This is because the gray dotted line is not as prominent as the benchmarks in the other graphs. It gets lost in the data and takes a second for the viewer to notice it is there. Making the benchmark line a different color would help make it stand out.