Monday, January 29, 2007

Record Linkage Graphical User Interfaces

Manual handling of duplicates in a database can be quite time consuming. It is important to find the right tool to help you speed this process. Or if you are building your own record linkage tool, it is always good to see what is out there, how GUIs are laid out and what the common features are.

The Link King:















The Link King’s graphical user interface (GUI) makes record linkage and unduplication easy for beginning and advanced users. The data linking neophyte will appreciate the easy-to-follow instructions. The Link King's artificial intelligence will assist in the selection of the most appropriate linkage/unduplication protocol.

Linkage Wiz:



LinkageWiz
is a powerful data matching and record de-duplication software program used by businesses, government agencies, hospitals and other organisations in the USA, Canada, UK, Australia and France. It makes it easy to link records across multiple databases and to identify and remove duplicate records within databases
TAILOR -
TAILOR is extensible, and hence any proposed searching method, comparison function, decision model, or measurement tool can be easily plugged into the system. We have proposed three machine learning record linkage models that raise the limitations of the existing record linkage models. Our extensive experimental study, using both synthetic and real data, shows that the machine learning record linkage models outperform the probabilistic record linkage model with respect to the accuracy and the completeness metrics, the probabilistic record linkage model identifies a lesser percentage of possibly matched record pairs, both the clustering and the hybrid record linkage models are very useful, especially in the case of real applications where training sets are not available or are very expensive to obtain, and Jaro's algorithm performs better than the other comparison functions.

The following three screen snapshots are the basic screens of TAILOR graphical user interface. The first screen allows the user to either generate a synthetic experiment using DBGen, perform a real experiment on a database, or repeat a previous experiment knowing its data files. The user then uses the second screen in order to select a searching method and a comparison function and tune their required parameters. Finally, the third screen allows the user to select the decision model he would like to apply and outputs the values of the measures if the experiment is on synthetic data.

Download PDF for screenshots of TAILOR here.

MatchIT -
matchIT incorporates our proprietary matching algorithms to ensure phonetic, miskeyed and abbreviated variations of data are detected. Results can be verified using comprehensive data auditing functions, drilling down to suspect data, identifying data anomalies, and filtering garbage and salacious words.














Fuzzy Dupes 2007

Did you know that your contact database typically contains 3-10% duplicates ?

These duplicate records result in unnecessary costs when sending out printed catalogs, are aggravating to your customers, create problems in the controlling, etc. With classical methods you have no possibility to locate these duplicates in your database.




Sunday, January 28, 2007

Machine Learning and the Hidden Markov Models (HMM)

What is a Hidden Markov Model? (from Answers.com)

A hidden Markov model (HMM) is a statistical model where the system being modeled is assumed to be a Markov process with unknown parameters, and the challenge is to determine the hidden parameters from the observable parameters. The extracted model parameters can then be used to perform further analysis, for example for pattern recognition applications. A HMM can be considered as the simplest dynamic Bayesian network.

In a regular Markov model, the state is directly visible to the observer, and therefore the state transition probabilities are the only parameters. In a hidden Markov model, the state is not directly visible, but variables influenced by the state are visible. Each state has a probability distribution over the possible output tokens. Therefore the sequence of tokens generated by an HMM gives some information about the sequence of states.

Hidden Markov models are especially known for their application in temporal pattern recognition such as speech, handwriting, gesture recognition and bioinformatics.

 State transitions in a hidden Markov model (example) x — hidden states y — observable outputs a — transition probabilities b — output probabilities
State transitions in a hidden Markov model (example)
x — hidden states
y — observable outputs
a — transition probabilities
b — output probabilities

Resources:

Machine Learning Links

Record Linkage and List Quality

What is Record Linkage:

Record linkage is the task of quickly and accurately identifying records corresponding to the same entity from one or more data sources. Record linkage is also known as data cleaning, entity reconciliation or identification and the merge/purge problem. This paper presents the “standard” probabilistic record linkage model and the associated algorithm. Recent work in information retrieval, federated database systems and data mining have proposed alternatives to key components of the standard algorithm. The impact of these alternatives on the standard approach are assessed. The key question is whether and how these new alternatives are better in terms of time, accuracy and degree of automation for a particular record linkage application.


Other names that mean the same thing: entity heterogeneity, entity identification, object isomerism, instance identification, merge/purge, entity reconciliation,
list washing, match/consolidate and data cleaning. I like the term "record linkage" and will refer to it as such from this point forward in this blog.

Seems clear that if you want to be thorough in your record linkage efforts you would implement a combination of deterministic and probabilistic matching methodologies. Using a straightforward name and address match such as the Firstlogic (now Business Objects) approach will usually be sufficient if you are a list vendor or mailhouse. But if you are at all serious about identity management you will step into the deep end and implement a probabilistic matching method. I've downloaded the Ferbl open source probablistic matching tool, but have yet to experiment with it.

But whatever method you use or software package you buy, the quality of your record linkage always ends up in how good you have configured your rules. This is not an off-the-shelf solution - it requires work.

I bet most organizations "record linkage problems" could have been avoided if enough forsight and initiative had been put on the original database systems, in establishing that unique key.

Well, I guess hindsight is in fact - 20/20.

One product that definitely contributes to an increased percentage of record linkage is the SSA-NAME3 product. As you'll see from their site, they have developed this name search tool which uses probabilistic matching but factors in how common or uncommon the name is. For example matching two Jose Garcia's in the city of Los Angeles is not the same as matching two Jose Garcia's in Iceland. They are probably the same person in Iceland and most likely not, in LA.

What is a Data Steward?

Data Steward defined:

The person responsible for a data standard. In this role, a Data Steward is charged by his/her Management to develop and maintain the data standard and to counsel Service personnel on the proper use of the data. He/she must: have a thorough knowledge of the subject matter of the standard, provide accurate and current electronic copies of data relevant to the standard, and weigh the pros and cons of comments received during review of the standard. He/she is authorized to defend or modify the standard as necessary in order to ensure its proper use.
Claudio Imhoff's definition and description of duties:
Steward - from Old English for "keeper of the sty", a sty ward.

Data Steward - Person responsible for managing the data in a corporation in terms of integrated, consistent definitions, structures, calculations, derivations, and so on.

Corporations are demanding better and better sources of data. The explosive growth of data warehousing and sophistication of the access tools are proof that data is one of the most critical assets any company possesses. Data, in the form of information, must be delivered to decision-makers quickly, concisely and more importantly, accurately.

The data warehouse is an excellent mechanism for getting information into the hands of decision-makers. However, it is only as good as the data that goes into it. Problems occur when we attempt to acquire and deliver this information. A major effort must be made in defining, integrating and synchronizing the data coming from the myriad operational systems producing data throughout the corporation. Who should be responsible for this important task? The answer for a growing number of companies is a new business function called Data Stewardship.

What is Data Stewardship?

Data Stewardship has, as its main objective, the management of the corporation's data assets in order to improve their reusability, accessibility, and quality. It is the Data Stewards' responsibility to approve business naming standards, develop consistent data definitions, determine data aliases, develop standard calculations and derivations, document the business rules of the corporation, monitor the quality of the data in the data warehouse, define security requirements, and so forth (see Table 1 for a list of the data integration issues determined by Data Stewards).

This data about data, or meta data, developed by Data Stewards can then be used by the corporation's knowledge workers in their everyday analyses to determine what comparisons should be made, which trends are significant, that apples have indeed been compared to apples, etc.

Just as the demand for a data warehouse with good data has grown, the need for a Data Stewardship function has likewise grown. More and more companies are recognizing the critical role this function serves in the overall quest for high quality, available data. Such an integrated, corporate-wide view of the data provides the foundation for the shared data so critical in the data warehouse. ...

Data Stewards are responsible for the following:
* Standard Business Naming Standards
* Standard Entity Definitions
* Standard Attribute Definitions
* Business Rules Specification
* Standard Calculation and Summarization Definitions
* Entity and Attribute Aliases
* Data Quality Analyses
* Sources of Data for the Data Warehouse
* Data Security Specification
* Data Retention Criteria
Crash Course on Data Stewardship:

Data Stewardship programs are implemented to reduce information technology costs and improve the value companies gain from their data assets. Stewardship programs focus on improving data quality, reducing data duplication, formalizing accountability for data, and improving business and IT productivity. An effective Data Stewardship program will rapidly improve the ROI from data warehousing and business intelligence efforts

Data Governance - IT or Business?

"Where does Data Governance fit into the Organization?"

This question appears to have two answers. "In Business" or "In IT". The answer I get most often when I ask the question is ... "In Business". Or "Business should own Data Governance".

I wish it was that simple.

What exactly does it mean for Data Governance to fit "In Business"?

This article seemed to take up the questions posed in my last post. The last paragraph sums it up and answers this question.

The best answer to the question "Where does Data Governance fit into the Organization?" is "It doesn't matter". Data Governance can be successful when managed by a business area or by an IT area.

The decision of who will manage the Data Governance program can be very important to the success of the program. However, it will not necessarily make or break a well-defined Data Governance program's likelihood of success. As long as the business areas and IT areas coordinate their efforts, use a Data Governance Council as a strategic resource, cooperate in strategic data management activities, and act in the best interests of the organization (data-wise), the placement of the management of the Data Governance program is not nearly the most important question that needs to be answered.

Wednesday, January 24, 2007

IT Departments Role in CDI

Introducing Customer Data Integration into an organization can be a bit daunting. A recommendation to anyone doing this is Jill Dyche / Evan Levy's book: Customer Data Integration which definitely builds the needed foundation for anyone's understanding of this subject. However, there are still aspects that need to be understood and certain functions clearly delineated.

What is the role of IT in CDI (Customer Data Integration)?

First a definition of IT:

information technology
n. Abbr. IT
The development, installation, and implementation of computer systems and applications.
"IT." The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. 24 Jan. 2007. http://dictionary.reference.com/browse/IT>
The development, installation and implementation of the CDI system is the responsibility of IT - Not the day-to-day upkeep of the data. As a Data Steward you must have the needed access to the data in order to uphold your responsibilities.

Tight coordination is needed between the Data Stewards and the IT Dept when the CDI project is in its early stages. Clear definitions should be established for the roles needed, responsibilities assigned and the needed functionality and access levels built into the CDI project.

Getting this established and clearly delineated at the onset is critical to a successful CDI implementation and will increase the mileage and speed of progress in achieving your goals with CDI.

Friday, January 19, 2007

Postalsoft Mailing Software: Compare Solutions

Here is a good comparison of the Firstlogic mailing products. I thought I had the professional suite but in looking at these it seems I am only getting the Business Edition options. I better call my account rep...

Postalsoft Mailing Software: Compare Solutions