Not everyone understands statistics. Not even going to college guarantees that you will be taught the subject. But you will be exposed to it in daily life, and having some base knowledge is a useful life skill.
In the Nov. 2 issue of Current in Carmel, a paid ad presented a chart of assessment test data for Carmel Clay Schools. The chart illustrates a distressing downward trend in these scores. Or does it? Readers are presented in incomplete picture and are asked to jump to certain conclusions. This is rhetoric, not logic. An explanation is warranted.
First, the vertical range (y-axis) of the chart ranges from 50 percent to 100 percent, not 0 percent to 100 percent as is to be expected. This is done to magnify the changes over time. It also wants the reader to interpret the latest results as almost absolute failure.
Second, there was no ILEARN assessment conducted in the year 2020. But there is a continuous line through that date, implying a data point that does not exist. Other visualization sins exist in this chart as well, but I will leave those to Edward Tufte to address.
Most important of all, this advertisement wants you to think that (Carmel Clay Schools) Supt. Michael Beresford is responsible. It willingly ignores critical questions that need addressing in order to answer that question: Were there any other events in the last two years that could have had a negative impact on assessment scores? Did these events affect other schools outside of Carmel Clay Schools in a similar way? Local media reports from this summer already established this as a statewide problem.
People need to think critically about the information that is presented to them. This was always the case, but now we live in an age of overwhelming information, which lets disinformation creep in. People should stop and ask themselves: What is the presenter trying to present and is this a valid interpretation? And: What other motivations could the presenter have?
Courtney Falk, Carmel