To what extent can we predict which university students will succeed and which will drop out? And what factors are likely to affect their grades as they progress through the course?
The starting point is previous academic achievement - that's the strongest predictor of university success, and that's why previous grades and entrance exams are used to select students. But, in fact, previous academic performance only accounts for about a quarter of the variance between students.
In other words, there must be a whole raft of other things affecting students' academic performance at university. So what are they?
A recent study was able to access information from over 55,000 university students across the United States, all under 25 years old. They had all completed a survey about their mental and physical health, using the American College Health Association National College Health Assessment. This survey covers a lot of ground including: alcohol, tobacco and other drug use, sexual health and orientation, weight, nutrition, exercise, mental health, personal safety / violence.
It also includes questions about sleep:
On how many of the past 7 days, did you get enough sleep so that you felt restored when you woke up in the morning?
In the past 7 days, how often have you awakened too early in the morning and could not get back to sleep?
In the past 7 days, how often have you felt tired, dragged out, or sleepy during the day?
In the past 7 days, how often have you had an extremely hard time falling asleep?
The researchers took all this information and looked at how each different factor predicted success. They measured success in two ways:
Whether the student had dropped a course in the last 12 months
The students' current Grade Point Average (GPA)
Dropping a course is included because it's a predictor of the likelihood that a student will graduate. Dropping one course, lowers the probability of a student graduating by 14%.
Firstly, students who reported sleep disturbances in the previous week were significantly more likely to have dropped a course within the previous 12 months. In fact, each additional day of sleep disturbance reported increased their probability of having dropped a course by 10%. This effect became even larger when looking only at first-year students. For them, each day of sleep problems raised the probability of having dropped a course by 14%.
For all students, each additional day of sleep problems resulted in GPA decrease of 0.02. This is even when all other factors - such as major stressors, hours working in employment, age, race, and gender - were held constant.
Comparing sleep with other risk factors
Dropping a course:
The most important factor determining the likelihood of having dropped a course was whether a student had received treatment for depression, anxiety or another psychiatric concern in the last 12 months.
After that, there are a whole raft of factors affecting drop-out which are all around the same level of risk. These include:
a diagnosis of ADHD
number of stressors
drug use: Marijuana, illegal use of prescription drugs, and other drug use (crack, sedatives, ecstasy, inhalants, etc)
being in an abusive relationship
The most important factors determining grades were: having received treatment for depression and/or anxiety, ADHD and marijuana use. For first year students learning disabilities, number of stressors, cigarette use and prescription drug misuse were also significant.
Again, then came a number of factors effecting students' grades, all around the same level of risk:
being in an abusive relationship
drug use other than marijuana (crack, sedatives, ecstasy, inhalants, etc)
Why don't we talk about sleep?
The takeaway point about these results is that lack of sleep is right up there as one of the key factors that affect academic performance. Students know this and they want information, but they rarely get it. In fact, whereas only 27% of students report having received information about good sleeping habits, 87% have received information about drug and alcohol use. Yet the current study shows that there is little difference between these factors in determining students' success at university.
More and more is coming out about the importance of sleep in academic performance. Total sleep time and sleep time inconsistency - interacting with stress - were found to be the highest predictor of undergraduate GPA here. Sleep, along with previous academic performance and class attendance, was a key predictor of grade performance in college students here.
And, most recently when the Seattle School District delayed the secondary school start time by nearly an hour, the the students gained an extra 34 minutes of sleep and their median grade average increased by 4.5%.
This is not a small problem
In this research, students reported experiencing an average of 2.4 days of sleep disturbance the week prior to being surveyed. That's the average across all 55,000 students. Academic performance is one thing, but we are rapidly discovering a whole host of of other health benefits - health necessities - that come with getting optimum sleep. The message is clear and simple: sleep for 8 hours.