Pundits frequently rail against the left-wing skew of the media. However, systematic evidence is hard to come by. Those quantitative studies that do exist are mainly of the US media. One famous study from 2005 later resulted in a book for the first author, Tim Groseclose (an economist at George Mason University). His
This paper makes an effort to quantify journalists' political orientation: https://www.science.org/doi/10.1126/sciadv.aay9344