A theory has been proposed for the structure of MSM news, called the "propaganda model," which can provide a framework for scientific investigation of ownership bias in news.

1988- PROPAGANDA MODEL

https://chomsky.info/consent01/

//The essential ingredients of our propaganda model, or set of news "filters," fall under the following headings: (1) the size, concentrated ownership, owner wealth, and profit orientation of the dominant mass-media firms; (2) advertising as the primary income source of the mass media; (3) the reliance of the media on information provided by government, business, and "experts" funded and approved by these primary sources and agents of power; (4) "flak" as a means of disciplining the media; and (5) "anticommunism" as a national religion and control mechanism. These elements interact with and reinforce one another. The raw material of news must pass through successive filters, leaving only the cleansed residue fit to print. They fix the premises of discourse and interpretation, and the definition of what is newsworthy in the first place, and they explain the basis and operations of what amount to propaganda campaigns. The domination of the media and marginalization of dissidents that results from the operation of these filters occurs so naturally that media news people, frequently operating with complete integrity and goodwill, are able to convince themselves that they choose and interpret the news "objectively" and on the basis of professional news values. Within the limits of the filter constraints they often are objective; the constraints are so powerful, and are built into the system in such a fundamental way, that alternative bases of news choices are hardly imaginable.//

1989- MANUFACTURING CONSENT

https://chomsky.info/19890315/

//The fact of the matter is, Ronald Reagan had a hands-off policy. In fact, Ronald Reagan probably didn’t even know what the policies were. The fact of the matter is, for the last- I mean the media had to put on a big pretense about this, but most of the population knew, that for the last eight years the country hasn’t had a chief executive. I think that’s a step forward in manufacture of consent, and in fact it’s maybe a sign of the future of political democracy. I think the United States made a leap into the future in the last eight years. If you could get to the point where voting is simply a matter of selecting purely symbolic figures, then you would have gone a long way towards marginalizing the public. And that pretty well happened. You had somebody who probably didn’t know what the policies were. His job was to read the lines written for him by the rich- what he’s been doing for the last thirty or forty years. And he seems to enjoy it and he gets well paid for it, and everybody seems happy, but to vote for Ronald Reagan is like voting for the Queen of England.//

THE FIRST RULE OF FIGHT CLUB IS YOU DON'T TALK ABOUT FIGHT CLUB

//Let me return to the prediction of the propaganda model that I mentioned...//

//...However well confirmed it may be, it’s not going to be part of the discussion, it’s going to be outside the spectrum of discussion, it’s very validity guarantees that for the reasons that I mentioned. And that conclusion, again, is quite well confirmed, and one can assume with reasonable confidence that that will continue to be the case.//

2009- TWENTY YEARS LATER

https://chomsky.info/200911__/

//
...
Ownership
Advertising
Sourcing
Flak
Anti-communism

EH/NC: What you refer to as the Propaganda Model’s ‘five filters’ requires some clarification. (a) Ownership and (b) advertising belong to straightforward institutional analysis — these are the kinds of institutional arrangements that predominate among US media firms and elsewhere. (c) Sourcing and (d) flak are two well-established processes to which any elite-serving media will adapt, whether we are talking about the elite US or British media or the elite media under Stalin and Hitler. On the other hand, (e) anti-communism, as a major theme of media production during the twentieth century, was reflective of the prevailing system of belief in the Western states, and has evolved with the collapse of the Soviet bloc since the first edition of Manufacturing Consent. In a crucial sense, and extending from the most minor comic books and cartoons all the way up to the highest academic discussions of the so-called Cold War (i.e. the system of propaganda known as the ‘Cold War’), anti-communism was a staple that provided content, narratives, heroes and villains. Since 1989, this staple has morphed into an array of substitutes. But the structural role that anti-communism and its successors have played, namely, the provision of an Enemy or the Face of Evil, remains as relevant as ever.
//

So all together we have a theory of ownership and selection bias in news.

And the web is nothing if not a study of structures for attention-seeking by media.

Between agenda-setting and attention mgmt, what else do you need to understand about the structure of MSM news?

The obvious question is: what structure of news is required to further free and coherent public participation in policy?