You're going to have to determine what the weighting factors should be, as a function of age of the data. How far back does the data go? How would you weight data that is 1 day old versus data that is a month old, or a year old, or a decade old? Asked another way - if yesterday's data is worth, say, 100 points in the weighting scheme, how old does data have to be for it to be worth only 50 points and hence counts only half as much? Once you figure out how you'd like to weight the age of the data then you can come up with a formula or table that reflects the weighting. |