I am currently a member of 40 LinkedIn groups mostly targeted at Master Data Management, Data Quality and Data Matching.
As I have noticed that some groups covers the same topic I wondered if they have the same members.
So I did a quick analysis.
With Master Data Management the largest groups seems to be:
- Master Data Management Interest Group with 2.818 members.
- MDM – Master Data Management with 2.333 members.
Using the LinkedIn Profile Organizer I found that 907 are members at both groups. This is not as many as I would have guessed.
With Data Quality the largest groups seems to be:
- Enterprise Data Quality with 784 members.
- The Data Quality Association (former European Data Quality Network) with 753 members.
Using the LinkedIn Profile Organizer I found that 189 are members at both groups. This is not as many as I would have guessed despite the renaming of the last group.
As for Data Matching I have founded the Data Matching group. The group has 235 members where:
- 77 are members in the two large Master Data Management groups also.
- 80 are members in the two large Data Quality groups also.
Also this is not as many as I would have guessed.
You may find many other similar groups on my LinkedIn profile – among them:
- Data Quality Pro.com with 252 members (main site has +2.000 members)
- Obsessive-Compulsive Data Quality (OCDQ) with 154 members (blog has heaps of visitors)

Today I stumbled over a company called 
In other words: The real world is not that simple and the picture of how households are forming does change.
John Smith is the ultimate Anglo common name, but if your favorite external business directory tells you that the 2 companies has the same mother and are modest size organizations, the possibility of John Smith being the same person having the same role at the same time in 2 companies is very high.
When a prospect comes to your site and tries to find information about your products, the first thing to do is very often using the search function. From deduplication of names and addresses we know that spelling is difficult and that sometimes we use other synonyms than used in the Master Data descriptions. Add to that the 
During many years of providing solutions for business directory match and tuning these as well as handling such match services from colleagues in the business I have very, very seldom seen a 100% match – even 90% matches are very rare.