Consumer Reports is removing its "recommended" designation from four Microsoft laptops and cannot recommend any other Microsoft laptops or tablets because of poor predicted reliability in comparison with most other brands.

To judge reliability, Consumer Reports surveys its subscribers about the products they own and use. New studies conducted by the Consumer Reports National Research Center estimate that 25 percent of Microsoft laptops and tablets will present their owners with problems by the end of the second year of ownership.

The decision by Consumer Reports applies to Microsoft devices with detachable keyboards, such as the new Surface Pro released in June and the Surface Book, as well as the company's Surface Laptops with conventional clamshell designs.

The four laptops losing their previous recommended status are the Microsoft Surface Laptop (128GB and 256GB versions) and Microsoft Surface Book (128GB and 512GB versions). Microsoft is relatively new to the hardware business, and this is the first year CR had enough data to estimate predicted reliability for the company's laptops.

Microsoft's estimated breakage rate for its laptops and tablets was higher than most other brands'. The differences were statistically significant, which is why Microsoft doesn't meet CR's standards for recommended products. The surveys are conducted annually.

Microsoft defended the reliability of its laptops and tablets.

"Microsoft's real-world return and support rates for past models differ significantly from Consumer Reports' breakage predictability," Microsoft said in an emailed statement. "We don't believe these findings accurately reflect Surface owners' true experiences or capture the performance and reliability improvements made with every Surface generation."

What the Numbers Mean

Consumer Reports' lab testing measures how well a laptop or tablet performs for a range of factors, including display quality, battery life, speed, and ergonomics.

Several Microsoft products have performed well in CR labs, including the new Microsoft Surface Pro, which earned Very Good or Excellent scores in multiple CR tests. Based purely on lab performance, the Surface Pro is highly rated when used either as a tablet or with a keyboard attached.

However, many shoppers care as much about reliability.

"Consumers tell us that reliability is a major factor when they're choosing a tablet or laptop," says Simon Slater, Consumer Reports' survey manager. "And people can improve their chances of getting a more dependable device by considering our brand reliability findings."

To get at reliability, the Consumer Reports National Research Center surveys our subscribers regularly. There are millions of these folks, and many of them supply us with information on hundreds of thousands of individual products, including everything from pickup trucks to washing machines.

A number of survey respondents said they experienced problems with their devices during startup. A few commented that their machines froze or shut down unexpectedly, and several others told CR that the touch screens weren't responsive enough.

The new studies of laptop and tablet reliability leverage data on 90,741 tablets and laptops that subscribers bought new between 2014 and the beginning of 2017. Predicted reliability is a projection of how new models from each brand will fare, based on data from models already in users' hands.