Americ Azevedo taught an "Introduction to Computers" class at UC Berkeley last semester that featured some of the hottest options in educational technology.
By visiting the course's websites, the 200 enrolled students could download audio recordings or watch digital videos of the lectures, as well as read the instructor's detailed lecture notes and participate in online discussions.
But there was one big problem: So many of the undergraduates relied on the technology that, at times, only 20 or so actually showed up for class.
"It was demoralizing," Azevedo said. "Getting students out of their media bubble to be here is getting progressively harder."
Skipping classes, particularly big lectures where an absence is likely to go undetected, is a time-honored tradition among college undergraduates who party too late or swap notes with friends. These days, however, some professors are witnessing a spurt in absenteeism as an unintended consequence of adopting technologies that were envisioned as learning aids.
Already, even as many academics embrace the electronic innovations, others are pushing back. To deter no-shows, they are reverting to lower-tech tactics such as giving more surprise quizzes or slashing their online offerings.
"Too much online instruction is a bad thing," said Terre Allen, a communication studies scholar and director of a center that provides teaching advice to professors at Cal State Long Beach.
This last term, Allen experimented with posting extensive lecture notes online for her undergraduate course, "Language and Behavior." One goal was to relieve students of the burden of furiously scribbling notes, freeing them to focus on the lectures' substance.
Yet the result, Allen said, was that only about one-third of her 154 students showed up for most of the lectures. In the past, when Allen put less material online, 60% to 70% of students typically would attend.
When it comes to lectures with enrollment in the hundreds, universities usually don't compel undergraduates to show up, or even lower their grades for poor attendance.
"This is one of the things that divide universities from high schools," Allen said. "Students are expected to be personally responsible."
Still, Allen said, to curb "the absentee approach to college," she won't put her lecture notes online this term.
If other teachers follow suit, that might make a difference to students such as Julia Bui, a 23-year-old single mother on track to graduate from Cal State Long Beach this spring. This last semester, for the first time in her college career, Bui frequently skipped one of her lecture classes.
Bui ditched for the kinds of reasons that many undergraduates say they do: She found the course boring, and she had other demands on her time. Perhaps the clincher in her decision was that her professor posted his detailed lecture notes online.
"All you have to do is just look over the presentations for 15 minutes and you can learn the material that way instead of coming to class," Bui said.
Doug Suda, 19, a student in Azevedo's UC Berkeley class last semester, said he skipped about three-quarters of the lectures, largely because he was busy with an off-campus job and was taking the course only to fulfill a business major requirement. At the end of the term, Suda crammed for the final exam by watching videos of about 15 of the lectures over three days.
"If I hadn't had that ... I would have probably failed the class," said Suda, who instead received a B-plus.
Kelly A. Rocca, an assistant professor of communication at St. John's University in New York and one of the few scholars who has recently studied American college absenteeism, said she suspects that skipping has reached an all-time high largely because of students' off-campus jobs and reliance on academic technology.
To combat ditching in her own classes, Rocca refuses to post notes online. With undergraduates, she said, "the more reasons you give them not to come to class, the less likely they are to come."
Statistics on class-skipping are scarce. But a UCLA survey of freshmen at 142 schools found that 33% said they skipped at least occasionally. (The survey, conducted last fall, also found that 43% frequently were bored and 58% had fallen asleep in class.)
UCLA researchers hastened to add that their figures were only rough measures because of limitations in their survey.
Other researchers have turned up evidence supporting the common-sense belief that skipping class tends to hurt a student's grades.
Lee Ohanian, a UCLA economics professor and winner of several teaching awards, said he notices that pattern in his classes. The frequent skippers, he said, often "are the ones who are doing just enough to get by. The ones who are getting the A's are in the front row at every lecture."