Sleep deprivation causes homicides

Nick Lanier
Fall 2023 — Information Expositions
4 min readDec 18, 2023

In the intricate world of data analysis, we sometimes uncover insights that challenge our understanding of societal issues. This blog post delves into one such pattern: a notable correlation between insufficient sleep and homicide rates across the United States. Leveraging rich datasets and detailed statistical analysis, I’ve unraveled a connection that offers new insights into public health and safety.

The investigation is anchored in three datasets: “us_counties.csv,” “analytic_data2021.csv,” and “Unemployment.xlsx”, together amassing almost 1,000 different variables. Among the plethora variables, I zeroed in on two: ‘Insufficient sleep raw value’ and ‘Homicides raw value.’

Using correlation matrices and linear regression analysis, I discovered a correlation coefficient of 0.33 between these two variables. This moderate positive correlation suggests that as sleep deprivation increases, so does its homicide rate.

But it’s the regression analysis that delivers the most striking insight. The slope of the regression line stands at 40.39, indicating that for each unit increase in ‘Insufficient sleep raw value,’ there is a corresponding increase of 40.39 units in ‘Homicides raw value.’

To bring these staggering numbers to life, I created a scatter plot with a regression line, vividly illustrating the upward trend of homicide rates with increasing sleep deprivation. This visual serves as a compelling representation of the data, making the abstract numbers more interpretable and impactful.

Identifying a correlation is one thing; establishing causality is another. This study, limited to data from 2021, faced challenges in proving temporal precedence due to the data’s single year entry. Despite this, I controlled for confounding variables to establish internal validity.

When you think of factors that influence homicides, you think of personal variables like poor mental health and alcohol abuse, as well as economic disparities and other crime trends. I didn’t have access to every possible confounding variable, or any way to determine additional variables that might complicate these findings, which is a limitation of this study. However, to determine that insufficient sleep is causing this increase in homicides, and not the factors that one might expect outlined above, I accounted for these variables which were included in the dataset, notably ‘Poor mental health days raw value,’ and still found a significant correlation.

The regression model, accounting for these factors, reveals that around 22.5% of the variation in homicide rates can be attributed to the combined effects of insufficient sleep and poor mental health days.

The calculated coefficient for sleep of a staggering 46.82 tells us for each unit increase in insufficient sleep, we expect to see an increase of 46.82 in homicides, while holding poor mental health days constant. The coefficient for mental health days, on the other hand, means that for each additional poor mental health day, we anticipate an increase of approximately 1.87 in homicides, while controlling for insufficient sleep. This is substantially weaker than the impact of sleep.

Both insufficient sleep and poor mental health days are significant causal predictors of homicides, with insufficient sleep having a notably larger impact per unit change than poor mental health days. Poor mental health days had the highest correlation from data we had access to, so the significantly higher correlation between sleep and homicides lack of sleep suggests a significant role of sleep deprivation in homicides.

The study’s limitations, including the inability to conclusively prove temporal precedence and the lack of data on all potential confounding variables, mean that our conclusions must be drawn cautiously. Nevertheless, the implications are too significant to ignore.

This exploration into the correlation between insufficient sleep and homicide rates serves as a reminder that public health strategies need to encompass a wide range of factors, including those we might not immediately consider, like sleep quality.

The implications of this analysis extend beyond the realm of data analytics, touching on aspects of public health and social policy. Since insufficient sleep is indeed linked to higher homicide rates, this finding could significantly influence how we approach crime prevention and health promotion. Interventions aimed at improving sleep quality could have far-reaching benefits, potentially reducing crime rates. Moreover, this insight opens up new avenues for research, prompting questions about the broader societal impacts of sleep deprivation. How does sleep deprivation affect mental health, productivity, or even broader social interactions?

In data analytics, we often find that the numbers tell us more than just statistical relationships; they reveal stories about our society and its well-being. This study is a prime example, shedding light on an important and unexpected public health concern, and its broader societal implications.

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