user11609: What approach would you recommend to calculate current tendency in opening position?
You have set of (move+year) values from games.
Amount of total games is unknown but will be somewhere between 1 and 100.
I can just sum some f(year) for each move and compare.
a) Would you do it differently?
b) If not, what f(x) would you use?

user12052: Would recommend choosing a year to serve as a base year, then calculating a weighted average based on that. For example, if we choose 2000 as our base year, and say Ruy Lopez was played once in 2000, twice in 2001, and three times in 2003, we would sum (1 * 0 + 2 * 1 + 3 * 3)/6 = 11/6.
Alternatively, you could also compute the median (which in this case would be 2). Or, you could graph the data entirely, which would probably give you the best picture.
This definitely sounds like an interesting study, good luck! Let me know if you have followups

11609: <p>What approach would you recommend to calculate current tendency in opening position?</p>

<p>You have set of (move+year) values from games.</p>

<p>Amount of total games is unknown but will be somewhere between 1 and 100.</p>

<p>I can just sum some f(year) for each move and compare.</p>

<p>a) Would you do it differently?
b) If not, what f(x) would you use?</p>
 12052: <p>Would recommend choosing a year to serve as a base year, then calculating a weighted average based on that. For example, if we choose 2000 as our base year, and say Ruy Lopez was played once in 2000, twice in 2001, and three times in 2003, we would sum (1 * 0 + 2 * 1 + 3 * 3)/6 = 11/6.</p>

<p>Alternatively, you could also compute the median (which in this case would be 2). Or, you could graph the data entirely, which would probably give you the best picture.</p>

<p>This definitely sounds like an interesting study, good luck! Let me know if you have followups</p>
