Understanding Backfill and Lookback Limits in Adobe CJA

[DhanA2]

Hello experts,
I can see multiple limits can anyone explain it with realtime scenario why we have these limits and major differences?
Customer Journey Analytics (CJA) Backfill limits:

Stitching Method Initial Backfill Duration Lookback Window Hard Limit for Backfilling Identities Replay Frequency Options

Field-based Stitching	Up to 13 months	1 day, up to 7 days	3 months	Daily, Weekly
Graph-based Stitching	Up to 25 months	1 day, up to 30 days	3 months	Daily, Weekly

@brian_au 

[Josh__Stephens]

Hi @DhanA2 

The stitching options available are based upon the CJA package your organization has.  The options available for each package are explained here.

[DhanA2]

This statement clarified my doubt: Correct me If I'm wrong 

The lookback window affects attribution analysis for campaigns, while hard limits restrict the volume of identifiable data processed.

[Josh__Stephens]

For stitching, the lookback window defines how far back CJA will look to build a  relationship.

For example,

Monday - Brand new visitor on mobile web, cookieID abc123.  Looks at site, doesn't log in.

Thursday - Same visitor returns from desktop, cookie ID xyz123.  Creates an account and logs.  loginID 1111

Friday - Same visitor returns from mobile web, abc123 and logs in (loginID 1111).

If a replay happens on Saturday with a 7 day lookback window, CJA will stitch abc123 & xyz123 into the same person loginID 1111.

If a replay happens each day with a daily lookback, the visitor would not be stitched together since the shorter lookback period wouldn't find a relationship.

This is separate from using attribution IQ in Workspace.  You can set this lookback & attribution model at the time of report processing.  Stitching would impact the attribution IQ results as People are stitched together in more accurate ways.