If you’re in charge of monitoring (and securing) your company’s network, chances are good you’ve had a discussion over whether to block employees from accessing certain websites, including social networks. Executives at many companies want to block websites that drain productivity, such as Facebook and Instagram. In theory, that doesn’t prevent employees from accessing those time-wasters via their smartphones—but at least they aren’t using work-issued devices for things other than work. But does blocking websites actually boost productivity? According to a new report from Spiceworks, the answer is “yes.” In organizations that place no restrictions on web activity, some 58 percent of employees spend at least four hours per week on websites unrelated to their job. That’s the equivalent of 26 workdays per year. But in organizations that block access to social media, only 30 percent of employees spend at least four hours per week on such websites. (Spiceworks based its data on a survey of more than 600 tech pros in organizations across North America and Europe.) Of those companies that blocked certain websites from their corporate networks, some 85 percent banned illegal and unethical sites; around 61 percent blocked dating sites, and 38 percent shut off social media. Personal instant messaging (34 percent) and video/music streaming (26 percent) constituted other targets. Roughly 96 percent of large businesses restricted access to at least one online property, compared to 81 percent of small businesses. There's also a security angle to this: some 38 percent of companies experienced "one or more security incidents" via non-work-related websites being accessed via a corporate network, according to Spiceworks. That's a powerful incentive for administrators and executives to keep sites locked down. Spiceworks found that big-business ban on websites translated into greater productivity gains—some 28 percent of employees at such firms spent more than four hours a week on “non-work” websites. By contrast, around 51 percent of employees at small businesses spent more than four hours a week on such sites. If you’re an executive (or business owner) who wants to justify blocking employee access to certain sites, data like this is powerful leverage in a policy discussion. For administrators, a policy to block sites can grow into a pain—there are always new URLs and apps to ban. As for employees—well, who doesn’t want to be more productive?