Rating sustum is something elusive as the audience into something that can be traded!

Media has more uncertainty then other markets and industries , they never know what is going to be the next hit and it has more of a risk more uncertainity.

Demographic information is stuff like gender, ethnicity. - This came from people in advertising. Most content used to be for everyone a wide audiacne now it is more targeted.

People used to send in letters to give feed back to media. - They would say what they like and what it means to them much more subjective.

Archilbald crossly in 1929 came up with a measuring format for radio audience.

C.E Hooper did phone calls to ask what people are watching now in the resent instead of asking what they watched yeast, - people forot - there is more acturacy this way.

Diary method - over a certain amount of time documenting their media consumption, really time consuming - alot of input from the participants- poeple might have forgoten - relies on memory - not completely trust worthy - had to collate the information can take a long time.

Portiibal people meter, most accurate data as it takes out of the humane roe element.
can't tell if someone is actually focusing on the Tv
exspensive.