Excel 2010 :: How To Merge Big Dataset That Is Split In Half

I am running 2 audits on aspects of patient care. The first audit records a unique number that identifies the patient, and then a series of answers on demographics, and other stuff.

The second audit also records the unique number, and collects some other data on the particular patient at a later point in time (medication usage, levels of pain etc).

So in theory both audits will collect different information on the same patients. In practice, some patients will be missed and there won't be matching data sets. The order of collection won't be the same either, ie Audit 1 might be in the order of Patient 1,2,3,4 etc but Audit 2 might be patient 2,4,1,3

For various reasons these two data collection tools are not linked, and I end up with a spreadsheet for audit 1 and a spreadsheet for audit 2.

I need to merge these so that I can see all of the data for a particular patient at a glance, and where the gaps are, and apply some statistics to it etc. I could sort both lists by the unique audit number so that they are in order, and then copy blocks of data over from one sheet to the next, but there will be records missing, i might make a mistake with the alignment, and I'm sure there must be a better way.

I am using Excel 2010. Each audit case has about 50 columns of data for Audit 1 and 30 columns for Audit 2 . There will be ~20 new records (Rows) created each week that I want to progressively merge.