In Coremetrics you can analyze specific kinds of visitors by applying Report Segments. For example, you can make a segment for visitors from a certain marketing channel or who made a certain kind of purchase. I like using Report Segments because you can browse nearly the full set of standard reports for your segment, while Explore segments only let you view a very limited set of metrics that you select up front. To access this functionality, navigate to Manage > Report Options > Report Segments.
Once you open this up, click the Create New Segment button to open another window presenting you with options to make your segment. Mostly it's pretty self-explanatory so this post is going to focus on their very idiosyncratic timing rules.
Persistent Report Segments
Think of Persistent Report Segments as "Future Reports." When making Persistent Report Segments in Analytics, the text states, “Process daily starting tonight and apply to reports for the most recent 93 days."
This sounds a bit like they can be applied retro-actively, doesn't it? In reality, they can’t. Persistent Report segments start the day after you create them, and are used to pull data from days after that. There is no way to apply them to dates before you made the segment – if you try, you will just receive an error message saying, “The selected segment is not available for the selected date range.”
To clarify further with an example, if you create a segment on Friday, on Monday you can view the segment to see the weekend's data. However, you can't use the segment to view the data from before the weekend. This segment will be available only from Saturday on, and you will be able to apply it going back up to 93 days ago. So if you make the segment and then a few months later use it in August 2012, you can pull June 2012 and July 2012 data, but you cannot pull January 2012 data, since it is outside of the 93 day window.
One-Time Report Segments
Think of One-Time Report Segments as "Past Reports." If you wish to look at historical data, you will need to create a One-Time Report Segment. You can then define your date range, though One-Time Report Segments state "Start date must be within the last 93 days and range cannot exceed 35 days." In other words, you can see data as long as it's from within 93 days ago, and the entire reporting range can't be for more than 35 days.
As an example, if you create a One-Time Report Segment in August 2012, you can apply it to data up to 93 days ago (June 2012). However, the segment can only range for up to 35 days, so it would be, for example, from June 1 through July 6. If you try to see a longer time period, you'll receive the message "The dates for a one-time segment must not span more than 35 days." That means that if you want to see historical data for longer than 35 days, you'll need to make a second One-Time Report Segment and stitch it together with the first one.
Unfortunately in Analytics there is not an option to make a One-Time Report Segment and then have it turn into a Persistent Report segment, or otherwise segment one month back and continue through the future. So if you want to see both past and future data, you will need to use a combination of these two segment types.