Time, September 3, 1945, pages 64, 66:

      RADIO      

Pioneer
    Detroit's WWJ was born August 20, 1920. Broadcasting was then mostly stutter and static, and reception was mostly a matter of cat's whiskers and crystals. When the station was just eleven days old, its listeners were invited to hold "wireless parties" in their homes, to hear the first U.S. broadcast of election returns. A month later, WWJ (then called 8MK) aired radio's first vocal program, a soprano singing The Last Rose of Summer.
    Ever since then WWJ has been scoring radio firsts right & left. It claims to have broadcast the first play-by-play accounts of baseball and football games, World Series game (1920), prize fight, full symphony concert (with Ossip Gabrilowitsch and the Detroit Symphony). Walter Hampden, Fanny Brice, Fred Waring, Ty Cobb, Lillian Gish and Thomas E. Dewey (singing with an Owosso church choir) made their radio debuts over WWJ.
    Last week WWJ celebrated its 25th anniversary, and reasserted its claim to being the world's first commercial radio station. That claim used to be pooh-poohed by Pittsburgh's powerful KDKA. This year the National Association of Broadcasters finally decided the question in WWJ's favor; KDKA, it said, was ten and a half weeks younger.
    The station, founded by Detroit News Publisher William E. Scripps, this year chalked up still another first: it was the first big network station to ban all electrical transcriptions.
NAB Reports, 1945, Volume 13, page 401:
RYAN  WRITES  TIME  MAGAZINE

    NAB President J. Harold Ryan has sent the following letter to Mr. Henry R. Luce, Editor of Time Magazine:

    In the September third issue of Time under the Radio Section on page 66 occurs the following statement:
"Last week WWJ celebrated its 25th anniversary, and reasserted its claim to being the world's first commercial radio station. That claim used to be pooh-poohed by Pittsburgh's powerful KDKA. This year the National Association of Broadcasters finally decided the question in WWJ's favor; KDKA, it said, was ten and a half weeks younger."
    While it is true that this year the National Association of Broadcasters published a Chronology of Radio, your correspondent apparently has drawn from it an entirely erroneous conclusion. The Chronology is a reprint from Broadcasting's Year Book of 1942. Since this publication is not available to those organizations who were planning salutes to Radio on the Twenty-Fifth Anniversary of the year when commercial broadcasting began we reprinted the Chronology, solely for their guidance. To imply that the mere reprint of a chronology amounts to a "final decision" on a disputed date of history is manifestly unfair to the stations involved and to the NAB. It was not the intention, nor is it the prerogative of the NAB to attempt to decide the relative claims of two pioneer broadcasting stations. The statement, therefore, that this Association decided the question in WWJ's favor is in error and does an injustice to KDKA. We would appreciate your making the necessary correction.
Journal of the Association for Education by Radio, October, 1945, page 23:

WWJ first--KDKA has long claimed the title of pioneer commercial radio station in the United States. It can make that claim no longer. The NAB has decided that the first commercial radio station was Detroit's WWJ which, call letters 8MK, was born August 20, 1920. No reference was made in NAB's decision to the claims of WHA, the pioneer educational station which, it is alleged, was on the air several years earlier.
Journal of the Association for Education by Radio, December, 1945, page 64:

NAB's Willard D. Egolf has written that the NAB was not settling officially the dispute between WWJ and KDKA, to which editorial reference was made in the October Journal. The Chronology of Radio which was reprinted by NAB, and which listed the earlier date for WWJ, was only for the guidance of stations and did not constitute an official decision.