Question:What is the Time Decay formula that web analytics packages use to distribute credit across the multiple sessions associated with a user before a conversion?Context:All web analytics packages like Google Analytics rely on the concept of:USERS visitors, ie unique cookied browsers. Users have many...SESSIONS visits, ie sets of pageviews within close time proximity.CONVERSIONS a success event such as a sign-up which can occur during a session.These analytics packages allow you to distribute the credit of a single conversion across all the preceding sessions because each played a part in leading the user to conversion. One such model is Time Decay, which gives a diminishing share of credit to sessions further from the conversion.Time Decay Visual: (1st session)       (conversion)more info on attribution models.Sample Data:I am assuming the data required would be:n - the total number of sessions a user has before a conversiont - the total duration of time from the user's first session to conversiontbc - the individual time before conversion for each session So for three different sample users, data may look like this:UserID  n   t   Session#    Timestamp   TBC Conversion in session?User1   4   12  1           2015-10-01  12  NoUser1   4   12  2           2015-10-06  7   NoUser1   4   12  3           2015-10-11  2   NoUser1   4   12  4           2015-10-13  0   YESUser2   3   4   1           2015-10-09  4   NoUser2   3   4   2           2015-10-09  4   NoUser2   3   4   3           2015-10-13  0   YESUser3   1   0   1           2015-10-14  0   YES
Time Decay Formula for Conversion Attribution
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