A guest post by Matt Sundquist, Founder of Plot.ly

This post details how, where, and when the death penalty has been applied in the United States. We’ll examine opposition to the death penalty (9 graphs), the deterrence argument (5 graphs), and trends in the death penalty and public opinion (4 graphs).

We used Plotly’s APIs for Python, MATLAB, and R to make these graphs. We used import.io’s Plotly integration to access and share data from the Death Penalty Information Center.

Part 1: Opposition To The Death Penalty

The death penalty is left up to and applied by states. For a visual representation of the geographical applications, study the map below made with Python. Texas executes more people than any other state. Hover your mouse to see data.

This bar chart breaks down the same data and shows the number of executions in each state. One report showed that 2% of counties in the U.S. have been responsible for the majority of cases leading to executions since 1976.

Homicide rates are higher in death penalty states than non-death penalty states.

Examining the data at a state level–as one researcher did for 1998 data–also does not demonstrate a deterrance effect.

Part 3: Trends in the Death Penalty

The United States is the only country in the G7 (major advanced economy) to still execute people. From figures in 2013, the U.S. ranks sixth in the world for the use of capital punishment behind China, North Korea, Iran, Iraq, and Saudia Arabia. The United Nations General Assembly has adopted resolutions calling for a global moratorium on executions. China, India, the United States, and Indonesia have consistently voted against the resolutions.

The number of inmates sentenced to death increased between 1980 and 2010.

Public Opinion

The Gallop Poll Social Series on Crime tracks public opinion on the death penalty. The data below was gathered from a random sample of 1,028 adults. The margin of error is ±4 percentage points, indicated by the error bars on the plot.

Opinions diverge on whether the death penalty is fairly applied.

This is an open question. Earlier this year in a death penalty case, Justice Breyer argued that it is “highly likely that the death penalty violates the Eighth Amendment.” Let us know what you think. Find us at feedback@plot.ly and @plotlygraphs.

Matt is speaking at Extract Conference in San Francisco, 30th October 2015. Use the discount code “Extract-Plotly” to get 10% off tickets.