Data Structure Vs Data Integrity

You're sitting at your desk, working on the latest Salesforce Release Notes and someone from management stops in to discuss a Conga report that was just pulled from the Org. Data is showing up in the wrong places and sometimes not at all. What's going on and how do you fix it?
First you need to define what issues are related to Data Structure and which are related to Data Integrity.
Our issue is that we want Salesforce to always be up to date and reflect reality (Best Practice, this should be everyone's goal) BUT (yes, there's a but sandwich in here) we also want to capture data during a transaction. This is an issue of Data Structure first.
Data Structure
Define the fields and data needed to generate the reports you need now (and plan ahead for the future). If you're asking yourself what does this really boil down to? The answer is easy - imagine how the data could be used a year from now. Ex. You have a lookup relationship with data that ties to your Opportunities. Should you consider migrating this data to a Master-Detail relationship? Would roll-ups be critical to reporting in the future? Understand the pros and cons of this update (refer to Master-Detail post for instruction on this process).
Our main issue is capturing a snapshot in time of the Parent Company at the time of the transaction. What are the attributes of that Parent Company? Are we running reports based on that data? If we're using it for analysis, the data will only be accurate up until the deal closes and then Salesforce is updated with the new Parent Company. You've just defined an issue with Data Structure. Create the needed fields (automate where you can with workflow rules/field updates). Congrats, you've solved the first issue which was Data Structure.
Now that your Opportunities show up to date ownership information, as well as the 'Owner at the time of the transaction', you're now ready to tackle the Data Integrity issues.
Data Integrity
Was the correct Parent Account listed in the 'Ownership at time of transaction' field? If the deal is old, are you able to utilize field tracking (Account History Report) on Parent Company to identify the Parent at the time of the transaction? Some behind-the-scenes work is harder for the Admin and may take longer than reaching out to your deal teams, but those teams are busy with deals. Isn't it better to wait until the final review to verify that there are no mistakes in the updated data, than to ask those teams to fill in blank fields with data? This is a great way to bring value to your team and also to create a culture of only going to the deal teams when no other access to the data exists.
Your Data Integrity issues are now resolved. Next up is to add the newly created fields to your Conga reports and update your templates. I've found that it's easiest to run the existing template, export the current template to work from and then click on your 'Reports' tab in Salesforce. Since Conga just utilized the report to pull your document together, the report(s) will be at the top of your Recent Reports List. This is a great shortcut if you're like me and you have 50+ templates kicking around in your Org.
Data Structure vs. Data Integrity are two very different issues and for those users that are not intimately tied to the data, all they are seeing is that Salesforce is wrong. Walking through the types of issues and proposed solutions to correct the problems is another great way to maintain management support/advocacy for Salesforce and to avoid negative perceptions relating to your data. No one wants to perpetuate a culture of poor data quality and terrible user adoption.