National HMIS Conference September 14th and 15th, 2004 Chicago, IL Sponsored by the U.S. Department of Housing and Urban Development 1 Understanding Unduplicated Count and Data Integration Presenters: Loren Hoffmann, System Administrator WI Statewide HMIS Ray Allen, Executive Director Community Technology Alliance
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Understanding Unduplicated Count and Data … HMIS Conference September 14th and 15th, 2004 Chicago, IL Sponsored by the U.S. Department of Housing and Urban Development 1 Understanding
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National HMIS ConferenceSeptember 14th and 15th, 2004
Chicago, ILSponsored by the U.S. Department of Housing and Urban Development 1
Understanding Unduplicated Count and Data Integration
Presenters:Loren Hoffmann, System Administrator
WI Statewide HMIS
Ray Allen, Executive DirectorCommunity Technology Alliance
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Topics to be covered:
Types of fields - and data qualityStatistical ConsiderationsAn “unduplicated Count”
OvercountsUndercounts
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Data Quality:
General tests:Completeness
NULL vs “something”
ValidityIs the data valid?Is the data “reasonable”?
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Data Quality:
Types of data fields:Picklists; yes/noText - numeric, alphanumericDate
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Data Quality: Picklists
Validity - must be item from picklistCompleteness - response/no response
Who updates the list?System administrator or userWhat happens to deleted/inactivated items
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Data Quality: Date field
Valid date; NULL valueDetermining Validity:
Control by format on entrymmddyyy 10152003mmmddyyyy Oct152004
Is date a valid dateIs it reasonable
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Data Quality: Text
Little that can be easily validated on a large scale
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Data Quality: Completeness
For a given field, how many NULLS are there?
For the entire databaseFor a specified period of timeFor a given agency/user
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Unduplicated Countand the Client identifier
• To generate an unduplicated count (or to merge systems), most HMIS systems create and/or generate a common client identifier.
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(UN) Duplicate Counts
How does your system manage the “unique client” or “unduplicated client count”?
You need to know the algorithm usedEvaluate the data elements that are used to generate the count
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Un-duplicated Counts Two possible errors
It is not magic or foolproof.Undercount the number of clients:
The system counts two client record entries as a single client when it really is two clientsOvercount the number of clients:The system counts two client record entries as two clients when it really is the same client
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Unique Client Count
Two possibilities:
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Unique Client Count
Put all the clients in the same room and count them;Make a list of all the clients that you know;
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Unique Client Count
Using:Client first nameClient last nameClient date of birthClient gender
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Un-duplicated CountsAn example - how many clients?
Using first name, last name, gender, date of birth
William Smith, male, 10-15-1973Bill Smith, male, 10-15-1973William Smith, male, no DOB
Consider: address, race, HH members, etc
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Statistical Considerations
Defining the universe:Number of client records in the system vs.Number of ACTIVE client records vs.Number of UNDUPLICATED client records vs.Number of valid responses for a given data element
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Defining the Universe:
Example:1200 client records1100 ACTIVE client records1000 UNDUPLICATED clients980 DOB fields have data500 Marital Status fields have data
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Defining the Universe:
DOB example - 980 of 1000 had a valid date, therefore:
If 70% of the 980 records are 18+ (adults) then the actual number of adults on the system is between 68% and 72% (margin of error is 2%)Marital status, with only 50% having information, has a margin of error of +-25%
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Issue:
What do I do with conflicting answers for the same client? e.g. different race, DOB, or response to a question like :
“Is client homeless?” with both a “yes” and a “no”Or DOB that is different
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Coverage of Data
Database statistics vs the “universe”Determine the relevant universe
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Merging Databases
Most HMIS systems are decentralized and will require some form of systems integration and/or data migration to obtain unduplicated counts, service utilization patterns and characteristics of homeless persons served.
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11 County Region of Northern California
Population = 7,512,499
Geographic Area = 10,691 (sq. miles)
Equivalent in size to the state of Maryland
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BACHICBay Area Counties Homeless Information Collaborative
Mission: To better enable policy makers, service agencies, and funders to understand and service the needs of the homeless within the communityGoals:
Obtain unduplicated regional count of homeless personsIdentify prevalence of cross-county chronic homelessnessUnderstand client movement across continuum boundariesAnalyze service usage across continuumsInform funders about effectiveness of sponsored programs in the regionLeverage HMIS learning and expertise across multiple communities; increase success factors, reduce risk factors
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BACHIC
Product: Regional HMIS Data WarehouseOutcomes:
Better planning and resource managementClearer vision of the present and future needs of the homeless
Sponsored by the Charles and Helen Schwab Foundation
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HMIS Implementations by County
ServicePoint- All locally hosted
except for ContraCosta and Monterey
Legacy System
MS Access
Metsys
Deloitte
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RHINO Data CollectionRegional Homeless Information Network
BACHIC group agreed to the collection of All Universal Data ElementsAll Program-Specific Data Elements
What each county has agreed to forward RHINO
All Universal & Program Elements except for Protected Personal Information (PPI)Exception: Year of Birth, Program Entry & Exit Dates and ZIP Code
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Data Warehouse and CountiesRegional HMIS Data Warehouse
San FranciscoMetsys System
San Mateo Daisy/HOPE
System
ServicePoint Stand-aloneLocally Hosted System
ServicePoint HostedSystems
Other Local Systems
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RHINO DesignEncryption(SSH2)
County HMIS System
Data Entry TransformationExtraction
Regional HMIS Data Warehouse
BACHICReports
INTERNETINTERNET
Standard Format
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Project PhasesVision
AutomatedReal-TimeFlexibleAccurate
Phase I Phase II Phase III
HardwareSoftwareTesting
ValidationOf Design
Pilot ofSanta Clara
County
ImplementationOf Select
Diverse Counties
All otherCounties
Phase IV
Gro
wth
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Design of SystemMinimize counties’ efforts
Especially ongoing duties/obligationsSecurity, privacyMultiple diverse HMIS systems
Different stages of implementationsDifferent data formats
Reporting Flexibility so as not to limit future reporting choices
Work flowProcesses and procedures for resolving exceptions
Linux Server
SQL Server
DAT72 Backup
Reg
iona
l HM
IS D
ata
War
ehou
se
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Transference of DataData from counties will be CSV format (min. requirement)Minimum encryption (128 bit) using SSH2 (Secure Shell Version 2)
Regional HMIS Data Warehouse
County HMISSystems
Double firewall for increased security
Future use of OpenSSL
(Open Source software)
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Regional Unique Identifier
Required for de-duplication of customers within 11 counties.Information from personal identifiable data elements.Uses a hash algorithm to encrypt ID.Key is created by 11 counties, unknown to data warehouse team.Can not be reverse engineered, is one way encryption.
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Data Integrity
Before data is merged, it will be checked for the following:
Each record/entity ID is uniqueRequired data elements have some valueDate formats are correct and values are reasonableCode values conform to HMIS Standard
Ex. Gender: Male=0, Female=1All data elements can be linked back to a unique person identifier within submitted data set
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