Sponsorship, or advertiser control of programming, was the predominant form of program financing in American commercial broadcasting in the 1930s; by the end of the 1950s, only a minority of programs were sponsored. Factors such as television's higher programming expense and the networks' increased interest in program control undoubtedly contributed to sponsorship's decline. However, another important cause, arising from within the broadcast industry itself, has not been well analyzed in broadcast historiography. Although reformers blamed sponsorship for overcommercializing broadcasting, some broadcasting industry insiders also were critical of it, believing it undermined broadcasting not because it was too commercial but because it eroded broadcasting's commercial effectiveness. Sponsored entertainment might serve advertisers' needs, but if audiences were alienated by heavy-handed sponsorship, broadcasting would not be able to sell them things.