The Hot R&B/Hip-Hop Songs chart ranks the most popular R&B and hip hop songs in the United States and is published weekly by Billboard. Rankings are based on a measure of radio airplay, sales data, and streaming activity. The chart has 50 positions.The chart is used to track the success of popular music songs in urban, or primarily African American, venues. Dominated over the years at various times by jazz, rhythm and blues, doo-wop, rock and roll, soul, and funk, it is today dominated by contemporary R&B and hip hop. Since its inception, the chart has changed its name many times in order to accurately reflect the industry at the time.HistoryBetween 1948 and 1955, there were separate charts published for Best Sellers and Juke Box plays, and in 1955 a third chart was added, the Jockeys chart based on radio airplay. These three charts were consolidated into a single R&B chart in October 1958.From November 30, 1963, to January 23, 1965, there were no Billboard R&B singles charts. The chart was discontinued in late 1963 when Billboard determined it unnecessary because that there was so much crossover of titles between the R&B and pop charts in light of the rise of Motown. The chart was reinstated with the issue dated January 30, 1965, as "Hot Rhythm and Blues Singles" when differences in musical tastes of the two audiences, caused in part by the British Invasion in 1964, were deemed sufficient to revive it.