How does the rating system work on websites?

Question

Algorithms

How does the rating system work on websites? For example, on ad sites? Is there any commonly accepted logic/calculus?
I need to implement a rating system on the ad site, which will depend on positive reviews and negative ones. I would like to know what happens if the number of negative becomes much more than positive, and so on.

Answer 1

The usual arithmetic mean is calculated. A table with the item_id and rate fields is stored separately.
The rating is

SELECT SUM(rate) as sumrate, COUNT(item_id) as cnt from ratings where item_id=345 group by item_id

$rate=Sumrate/cnt

Answer 2

1. Draw the graph you need.
2. Choose a function for it.
3. Match the argument (cf. arithmetic/ratio/%/...)
For example, R = 10lg(positive/negative)