Consumer Reports currently tests about 850 consumer electronic products every year, in a dozen or so categories. We cover everything from TVs to cell phones, computers, digital cameras, and newer emerging categories. No one conducts hands-on tests of as many products as we do.

We decide which product categories to test based on current trends and on what CR members are interested in buying. Our experienced product specialists consider market data to help them select specific models, with a focus on representative brands, price ranges, and important features. They also contact manufacturers to make sure products will still be available when our ratings are published.

As with all test programs at Consumer Reports, the electronics program buys virtually all products at retail, like any consumer. That enables us to remain completely impartial and unbiased. Our secret shoppers visit stores across the country to make their purchases, without revealing that the products are destined for the Consumer Reports labs. They have to come up with some creative stories to explain why they're buying a dozen cameras or five big-screen TVs!

We also provide information on the services integral to the use of electronic products, including cell-phone carriers, internet service providers, cable and satellite TV providers, and computer tech support. The Consumer Reports product and service testing center regularly surveys consumers to see how satisfied they are with those services overall and in specific areas such as cost and quality.

For our most popular categories, we produce new ratings almost every month, and we update our ratings of other types of products several times a year. We also test innovative, high-interest products — such as the latest Apple iPhone — individually as soon as they are available. When time is of the essence, we occasionally buy a new product directly from the manufacturer before it is released to stores, but we always test a retail model when it becomes available to validate the results on the pre-retail sample.

We conduct our tests in laboratories designed for the demands of specific products. For example, TVs are tested in rooms with controlled lighting and a video distribution system that feeds various signal sources to the sets simultaneously to ensure a consistent experience. We evaluate audio products in environments that simulate a typical living room setting and in an anechoic (echo-free) chamber that isolates the sound produced by a device. Cameras and camcorders are tested in studios designed to simulate the wide range of shooting environments and lighting that you'll encounter in normal use.

The vast majority of products are tested at our headquarters in Westchester, New York, but we also share test results with our partners in International Consumer Research & Testing, a consortium of international consumer organizations.

Products are tested by engineers and technicians with years and sometimes decades of expertise in their field. They work with the products for several weeks, putting them through a battery of objective tests using scientific measurements, along with subjective tests that replicate the user experience. We test products against existing industry or government standards and develop our own benchmarks when we encounter new technologies or issues that require further testing. All models within a category go through exactly the same tests, side by side, so they're judged on a level playing field and test results can be compared.

Testers focus on a product's primary function (evaluating image quality for TVs and cameras, for example) and some secondary functions, too (sound quality for TVs or photos shot with a cell-phone camera). They evaluate whether features add to usability or just make an item more complicated. They check ergonomic functions (how intuitive controls are and how comfortable a keyboard is) and they consider other relevant attributes, such as battery life or speed.

We use a product as any consumer would. For example, we assess how long a laptop computer's battery will last when running everyday applications, such as word processing and photo editing, or how quickly a digital camera can shoot photos at a fast-moving soccer game.