Leading granola bar brand Nature Valley managed an enviable feat this summer: They released an ad that quickly went viral, collecting more than three million views on Youtube and driving headlines around the web. As you might recall, it contrasted what kids say they do for fun these days—play video games, watch TV, text with their friends—with what their parents and grandparents did for fun as children. The ad shows older generations reacting with mortification to their young descendants’ odes to technological entertainment.

Those who share their horror at the habits of today’s kids may find a bit of comfort in a new article in the journal Child: Care, Health and Development. According to two researchers from the University of Mississippi, the time American kids spend watching TV and videos on an average day declined between 2001 and 2012. The data come from several waves of the National Health and Nutrition Examination Survey, which asked the parents of a large, nationally representative sample of kids this question: “Over the past 30 days, on average about how many hours per day did [your child] sit and watch TV or videos?” Between the 2001-2002 wave and the 2011-2012 wave, there were statistically significant decreases in mean TV viewing for both preschoolers (ages two to five) and older children (ages six to 11).

The good news for screen skeptics ends there. The documented decline was very modest for older children (on the order of eight minutes a day), and a closer look at the numbers in individual survey waves suggests that the decline may prove to be less a long-term trend than a short-term blip. As of 2011-2012, preschoolers were watching about an hour and forty-five minutes of TV/videos daily, on average, and older kids were watching just over two hours. And the measure does not include the time kids spend using smartphones, computers, tablets, video games, etc.

So how bad is screen time, really? Decades after the advent of TV, it’s still surprisingly hard to answer that question. Economist Emily Oster has noted that the “many, many studies that show associations between time spent watching television and health and development outcomes” suffer from selection issues:

The amount of TV children watch is not randomly assigned. In the general population, kids who watch a lot of TV — especially at young ages — tend to be poorer, are more likely to be members of minority groups and are more likely to have parents with less education. All these factors independently correlate with outcomes such as executive function, test scores and obesity, making it difficult to draw strong conclusions about the effects of television from this research.

For parents, the more helpful answer Oster gives is: It depends. That applies to both the screens and the alternative activities. Is the screen transmitting an educational show like Sesame Street, or just Youtube videos of racecars? Angry Birds or an app teaching toddlers to recognize letters? And if your kids weren’t looking at screens, what would they be doing instead? If the answer is “playing outside” or “building Lego towers,” they might be better off putting down the iPad. But if the realistic answer is, in Oster’s words, “being yelled at by an overtired parent who is trying to get dinner ready,” then a little screen time probably won’t hurt.