Highschool graduation rate in USA

Twitter is a popular platform used by governments and leaders to communicate with public. Since the character limit for a tweet is limited, it makes sense to convey the intended information through charts rather than boring wordy reports with statistics. Here is one such tweet from Dec 2015 from WhiteHouse

Audience and intent – This chart is intended for public who is interested and constantly evaluating government’s performance. The Whitehouse wants to convey that the high school graduation rate is the highest in 2015 than it has ever been and implicitly highlight this as an achievement of the government.

Is the chart meeting the purpose?  To a certain extent and to people with not so keen eye for detail, yes – this chart serves the purpose. However, the chart does not represent high school graduation rate data in its entirety and is subject to speculations.

Critique –

  • The type of chart used is vague. A column-like chart is represented using books with a 3D effect. 5 books represent 75% and 16 books represent 82% which is quite absurd.
  • The graduation rate is represented as a percentage. A percentage of what? I am assuming that it is relative to the number of students enrolled in 12th grade.
  • Thinking further, I would want to know if there is any change in number enrolled for 12th grade. I am assuming the proportion of high school aged section in a given population does not change drastically over the years,  so ideally as the population grows, the number of people/kids in high-school-age-group also increases. If there is no increase in the number enrolled with passage of years the chart seems to be misleading.
  • Also, this chart does not give out any information regarding the drop outs. For example, a school has 120 students for 11th grade out of which 20 dropped out. 99 students out of the 100 who were promoted to 12th grade passed the exams may imply the high school graduation percentage is 99% (99/100)  or 82.5% (99/120).

Betterment – In chart-making, choosing the appropriate form to represent the data on hand is of utmost importance. Ideally a line chart is suitable to show subtle changes in rates over time. However for the high school graduation rates we have different parameters involved. I would like to see in a given year the number of people between the years 17 to 21 years and the percentage of them with high school diploma. To represent these details, I would use a bar graph. Y axis represents the population number scale (number of people between 17 – 21 years) and X axis represents year. Each bar is stacked, i.e divided into 2 stacks with different colors, each color stack representing the number of people with high school diploma and without high school diploma respectively.

 

References:

Washington Post – Highschool graduation rate hits an all time high

Whitehouse archives – More students are graduating than ever