Data analysis begins with understanding the available data. To social scientists, this usually involves understanding your data type — nominal, ordinal, scalar, ratio. Web analysts, however, must always be concerned with the level of measurement as well — page level, session level, user level. If Omniture SiteCatalyst is your data source, understanding SiteCatalyst’s levels of measurement is key to being a good analyst. Those esoteric SiteCatalyst variables: sProps, Success Variables, and eVars, are easy to remember once you’ve seen their levels of measurement and how they’re assigned.
SiteCatalyst Traffic Variables (sProps)
sProps are page-level variables that identify properties of specific pages; in data-warehousing parlance, they are equivalent to page-level dimensions. In practice, the Page Views, Visits, and Unique Visitor metrics can be broken down by sProp (though if you want more than 20, it’ll cost you, and there’s a max of 50) and any two sProps can be cross-tabbed. Several sProps are pre-defined: Page Name, Pathing, Server, Browser, Country, etc. sProps are not persistent across pages… obviously, you wouldn’t want Page Name carrying over from one page to another.
SiteCatalyst Success Events
Success Events record the number of times users complete specific actions on your site; in data-warehousing, these are your metrics. Pre-labeled or “standard” Success Events include Revenue, Orders, Units, and Cart Additions. Registrations might be another example of a Success Event common to many Web sites.
SiteCatalyst won’t allow you to break down or analyze a Success Event by an sProp because Success Events are session-level variables and sProps are page-level variables. But keep reading…
SiteCatalyst Conversion Variables (eVars)
eVars are persistent variables that allow you to break down Success Events in the same way sProps allow you to break down the Page Views and Visits metrics. Once an eVar is assigned, that variable persists until you tell SiteCatalyst to clear that value or until the cookie is lost. An eVar could therefore be used as either a session-level or user-level variable / dimension, depending on how you choose to assign the eVar value. Examples of where you’d use an eVar would include campaign tracking and affiliate tracking.
Interestingly, while you can overwrite an eVar, SiteCatalyst is aware of all values of that eVar it’s encountered for that sessions… allowing you to attribute Success Events to the first, last, or all values of an eVar for that session (an option you can set in the Admin console). Also, all eVars that are populated get credit when a Success Event occurs.
Kudos to Adam Greco’s Inside SiteCatalyst blog for getting me over the hump.