The relationship between media performance and market structure has long been a major concern by many media economists who believe that media performance is determined by market structure. However, these analysts disagree themselves about what kind of relationship exists between media performance and market structure. Some media economists assert there is a positive relationship between market concentration and media performance, while others don ’t take such a positive view about market concentration and instead see a negative relationship between market concentration and media performance (Adams﹐1993 ; Burnett﹐1992 ; Coser et al.﹐1982 ; Davis & Walker﹐1990 ; Litman﹐1979 ; Peterson & Berger ﹐ 1975 ; Rothenbuhler & Dimmick﹐1982 ; Ryan﹐1985 ; Schumpeter﹐1950 ; Bagdikian﹐1985 ; Compaigne﹐1985)。
This study investigates this issue by examining market competition and its relationship with content diversity of the prime-time dramas by the three TV networks in Taiwan. The data regarding the prime-time dramas from 1990 to 1997 were collected for data analysis of this study. The results support a positive relationship between market competition and content diversity of TV dramas. The implications of the findings from this study were discussed in the paper.