The term 'kind of rating' can refer to two different ratings systems. The first is the Nielsen rating system, which is a seven-letter system used to measure television viewership. It is based on a sample of households and is used to determine the popularity of television programs. The second is the EPA rating system, which is a three-letter system used to measure the energy efficiency of appliances. It is based on a set of standards established by the U.S. Environmental Protection Agency and is used to help consumers make informed decisions about their purchases.