Children who read regularly for pleasure, who are avid and self-directed readers, are the holy grail for parents and educators. Reading for pleasure has considerable current and future benefits: Recreational readers tend to have higher academic achievement and greater economic success, and even display more civic-mindedness.

But recreational reading is on the decline. According to a National Endowment for the Arts report based on longitudinal data from a series of large, national surveys, the rate at which teens voluntarily read for pleasure has declined by 50 percent over the last 20 years. Reading now competes for children’s time with many other alluring activities, including television, social media, and video games. Most leisure time is now spent in front of a screen.

To ensure that kids are spending at least some time every day reading, classrooms across the country have instituted student reading logs, which typically require kids to read for a certain amount of time—about 20 minutes—each night at home and then record the book title and number of pages read. In some cases, parents must also sign this log before their child turns it in to the teacher.

The goal of these logs is to promote the habit of recreational reading, or at least to create the appearance of it. The basic idea seems to be this: If kids who read regularly gain significant benefits, then it should be mandated that all students read regularly so they, too, can enjoy those benefits.

For example, in a post on her blog for parents, one fifth-grade teacher explains:

Our first reading unit this year is all about developing independence as readers. We have already been busy learning and reviewing things that powerful readers do. We know that reading, like any other skill, is developed through practice. Today we learned that powerful readers keep and analyze reading logs. We will be logging our reading at school and home each day. I am asking students to keep track of the amount of time they spend reading at home each week. They are required to read 100 minutes per week.

Unfortunately, this well-intentioned strategy may have serious pitfalls.

As a psychologist (and a parent), I have long opposed reading logs because of abundant research on the negative effects of external controls (such as rewards, deadlines, and assigned goals) on intrinsic motivation. In other words, when motivation to do an activity comes from outside, via rewards or mandates, it tends to undermine people’s interest in doing that activity for its own sake. This decline in motivation ultimately affects enjoyment, creativity, and even performance.

This research would suggest that reading logs have a similar effect on children’s reading habits, especially their desire to read for fun, making reading less of a pleasure and more of a chore. Imagine telling your child that she must draw pictures for at least 20 minutes daily—and also record how much time she spent drawing and how many different colors she used.

Until recently, however, there were no formal studies testing whether or not reading logs were actually promoting reading. A study published a few years ago, to surprisingly limited attention, in the Journal of Research in Education found that, indeed, reading logs can have a detrimental effect on students’ interest in and attitudes toward reading.

In the study, more than 100 second- and third-graders in 14 classrooms were divided randomly into two groups by class: The first was given a mandatory reading log, the second, a voluntary log. The students in the mandatory group were assigned to read each night a minimum of 20 minutes, to record their reading in the log, and to get a parent signature. The students in the voluntary group were encouraged to read, but teachers emphasized that the reading log was completely optional.

Students were tested to measure their interest in and attitudes toward reading both before and after the study. The results? Students assigned the mandatory log showed diminished interest in recreational reading and also more negative attitudes toward reading after the study concluded. In contrast, the voluntary group showed an increase in both interest and positive attitudes. Although this study wasn’t exhaustive, it suggests that reading logs may undermine their intended goals.

“When reading is portrayed as something one has to be forced to do,” the authors write, “students may draw the conclusion that it is not the kind of activity they want to engage in when given free time.”

This unintended effect of reading logs can catch parents off guard. Alesia Coward, a mother of a student in a highly ranked public elementary school, wishes she had objected to the reading logs required by her daughter's teacher: “Reading logs ruined my reader. [My daughter] used to love reading but when it became something she had to do, she stopped doing it for fun and only read as much as the teacher required.”

Similarly, the attorney and blogger Sarah Blaine writes: “[My daughter] started kindergarten as a lover of books. My biggest concern … was how to pry her away from books. But within weeks, the reading log began to change all of that: ‘Mom, am I done with my fifteen minutes yet?’ ‘Mom, why do I have to write this?’ ‘Mom, I don’t know what to say.’ And worst of all: ‘Do I HAVE TO read?’”

Compelling children to read may improve their reading skills, which is undeniably important, but mandated reading does not bring the same benefits as when children themselves choose to read. Worse, it may even diminish their interest in reading at all.