BAR GRAPHS , ANYONE ? Written by Michael Paolillo
At some point , after slaving away , beating back the failures , and tasting the sweat success of a scientific discovery , we must ask ourselves , ‘ How do I present this to other people ?’ I ’ m referring to the visual representation of data .
The current trend in science seems to be that we compile our western blots , cell counts , fMRI scans , or what have you , into one bar graph and top it off with an error bar . You might be nodding your head and recalling your own data being represented in this way . So what ’ s the big deal ? Nature , Science , and Cell do not seem to care , right ? I recently had a conversation with a friend who is working as a cell biologist investigating Alzheimer ’ s disease about this topic and his opinion was that we should represent the data so that they are easy for the reader to understand . Some people go so far as to suggest that if you want to show a difference , you can zoom in on the data to create the appearance of a larger distance between groups , and to do the opposite to show put , a scatter plot bares your data in its pure , naked , raw form . This can be unnerving for a scientist who opens himself to the possibility of greater scrutiny with a scatter plot compared to a neat and tidy box plot . As my friend rightly noted , if an experiment has a low sample size , a scatter plot looks silly with only measly five dots and that might not be received as well by other researchers compared to the traditional bar graph . However , a scatter plot tells the reader so much more than a bar graph .
This image below is from an article written by Dr . Christina Szalinski . What we see is that the same bar graph ( seen on the left ) can be made from starkly contrasting data sets . To no difference . Is this something that we should be doing ? What alternatives do we have to the ever present bar graph ? Well the answer is that there are actually quite a few options . The bar graph is but one visual tool among many . I would like to focus on the merits of the scatter plot . Simply put it simply , bar graphs make it difficult to see what is happening . Is there an outlier pulling my data away from the mean ? Do I have different sample sizes between my control and experimental groups ?
14 | NEUROMAG | July 2016