An analyst is assembling data for use in her firms expectations-setting process. Several historical measures have been collected and used to set expectations on inflation and consumer consumption trends. Previously, only the most recent 25 years of historical data concerning these measures had been collected and analysed. Now, an executive has suggested extending the starting point of the data 25 years further back to make the overall analysis more robust. Discuss why the inclusion of the additional data may present problems for the expectations-setting process despite the requests objective of making the analysis more robust