Chart and graph types in healthcare field documentation

¶ … Graph

Albendazole Therapy and Enteric Parasites in United States -- Bound Refugees

Steven J. Swanson, M.D., Christina, R. Phares, PhD., Blain Mamo, M.P.H., Kirk E. Smith, D.V.M., PhD., Martin S. Cetron, M.D., and William M. Stauffer, M.D.

New England Journal of Medicine 2012; 366: 1498-1507

This article details a review of data collected for refugees from Africa and Southeast Asia immigrating to the United States from 1993-2007. The data looks at parasites in refugees before and after a mandate by the Centers for Disease Control and Prevention in 1999 that all refugees bound for the United States receive a single dose of a drug called albendazole (600 mg) that targets and kills many intestinal parasites.

Plot-Chart

The article presents data in a figure labeled Figure 1 on page 1503. The chart is shown below:

The data in the chart in Figure 1 depicts graphically information contained within Table 3 on page 1504 of the publication. The data in the table shows the percent of refugees with different types of intestinal parasites before mandatory treatment and after mandatory treatment. The study looked at a total of 26,956 refugees of which 22,586 were treated with albendazole and 4370 were untreated. The data in Table 3 splits the population into tables for Africa and Southeast Asia. The chart in Figure 1 combines the data showing the total percentages of patients with parasites with and without treatment for both the continent of Africa and Southeast Asia.

Questions

Identify the type of chart or graph and what is this type of chart of graph usually used to depict.

The chart in Figure 1 is a summary bar chart where each specific parasite type is compared as a simple bar for all refugees showing the percent of refugees with that parasite before and after the treatment protocol was implemented. The X-axis is not indexed and simply displays the type of parasite in no particular order. The Y-axis shows the percent of refugees with a parasite and each grouping of before and after treatment are displayed as a pair with the parasite labeled beneath the pair of columns.

Was the proper chart or graph used to present this data? Why or why not?

The chart in the article is the best way to present a graphical image showing the comparison between the pre- and post-treatment groups of refugees. The summary bar chart condenses the tables of data without error bars or statistics to show the graphical difference between percentages of patients with a type of intestinal parasite in the years before and after the treatment regimen. The simple bars grouped above the individual parasites allow the reader to see the drastic differences in column height and conclude that there is a difference in the numbers of patients with a given parasite for most of the different organisms.

Was this the best way to display the data? What other types of graphs could have been used?

The summary bar chart was the best way to display the data because the data groupings are separate points and are not a trend or based on a timeline. Each set of data points is an individual type of parasite and the chart is used to compare data only within that parasite type. A pie chart would not have been appropriate since there is not a total percentage of an organism in the comparison. In addition, a linear graph showing changes over time would not have been appropriate for the data since there are only two time points. It would be possible to present the data as a simple summary bar chart showing the difference in the percentage of each organism before and after as shown in the chart below:

The problem with the presentation in the chart above is that the relative changes expressed between the different types of organisms is not as drastic in appearance as the gaps shown in the data expressed in the chart within the publication. It is also possible to plot the difference as a percentage drop as shown in the chart below:

The problem with expressing the data in this percent decrease is again that the drastic changes between the patients with and without each type of parasite before and after the treatment protocol was implemented are not demonstrated and the graphical format makes the demonstration of the five-fold increase in Entamoeba difference difficult to show with the other data sets.