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Trutz Haase
Jonathan Pratschke
Feline Engling
EMCDDA
Methodological Toolkit for the Estimation of the Number of People in Drug Treatment
Presentation to National Focal Points, EMCDDA, 24th -26th June 2013
Trutz Haase
Jonathan Pratschke
Feline Engling
BACKGROUND TO THE STUDY
Phase 1 of the Study:
� Development of a Generic Mapping System
� Workshop in January 2012 – 8 Focal Points participating
� Final Report in July 2012
Phase 2 of the Study:
� Development of a Methodological Toolkit
� to assist national Focal Points in dealing with double counting
� to improve national estimates along the lines of the Generic Mapping System
A SAMPLE MAP OF A COUNTRY’S TREATMENT SYSTEM
Outpatient Network
Specialised Treatment Centres
Low Threshold Agencies
PrisonsOpioid
Substitution Treatment
General Practitioners
Day Care Centres
Country
Inpatient Network
Hospital: Detoxification/
Emergency
Hospital: Rehabilitation/
Psychiatric
Prisons
Residential Communities
Therapeutic Communities
Total Drug Treatment
A GENERIC MAPOF SERVICE PROVISION AND TREATMENT DATA
Sub-total: Outpatient Network
Specialised Drug Treatment Centres
Low-threshold Agencies
Treatment Units in Prisons
Opioid Substitution Treatment
Other Outpatient Treatment
General Practitioners
General Health Care Centres
Country
Outpatient Network
Sub-total: Inpatient Network
Medical Detoxification Treatment
Hospital-based Residential Drug Treatment Units
Treatment Units in Prisons
Other Inpatient Treatment (1)
Other Inpatient Treatment (2)
Therapeutic Communities
Residential Drug Treatment Centres
Total Drug Treatment
Inpatient Network
A SAMPLE MAPOF SERVICES PROVISION AND TREATMENT DATA
WHICH INFORMATION? THE BASIC “BOX”
repNR Unit Count M rep NR Patient Count M
calcTDI Unit Count L calc TDI Patient Count LL
Units Patients
Comment Comment
Generic Category Country-specific Category
Source Indicator
calc calculated
rep reported
est Estimated
nnn Source
?? Check
Evaluation Flag
HH Very high
H High
M Medium
L Low
LL Very low
ADVANTAGES OF GENERIC MAPPING SYSTEM
� Same map/format for each country
� You understand your own map/data, you understand everyone else’s
� Parallel use of generic and country-specific terms of classification
� Clear distinction between where information is missing (ni) and valid zeros (0)
� Thus drawing attention to missing information (with positive knock-on effects)
� Data can be aggregated to country level sub-totals and totals
� Data can be aggregated across groups of countries and EMCDDA-wide
� All data can be instantly shown on a per 1,000 capita basis
� Cross-country per capita calculations can be used for evaluation of counts
� Data can be easily updated
� Standardised reports can be easily produced
TASKS FOR PHASE 2 OF THE PROJECT
� The challenge ahead is to derive appropriate algorithms for estimating missing
data and to optimise country-specific estimates.
� Particular attention needs to be paid to the sensitivity of the Generic Mapping
System to double counting.
� Hence the Focus of Phase 2 is on developing a “Methodological Toolkit for the
Estimation of the Number of People in Drug Treatment”
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSPDU PREVALENCE ESTIMATES (1)
� Definition of PDU
� Most countries have adopted EMCDDA definition, though some continue to use alternative (historically-motivated) definitions.
� Estimation Basis: Large variations in data used, including:
a) police reports related to opioids and/or other illicit drug use
b) drug-related deaths
c) substitution registry and/or other OST related-data
d) drug treatment data from inpatient, out-patient and other drug treatment facilities
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSPDU PREVALENCE ESTIMATES (2)
� Multiplier Construction
� General population surveys unsuitable, hence employment of either capture re-capture (CRC) or respondent-driven sampling (RDS) methods
� Accuracy depends on both the accuracy of the base indicator and the nature of the survey used to calculate weights/multipliers
� Surveys tend to be infrequent and limited in size (both institutionally and geographically)
� Resulting PDU estimates tend to have large confidence intervals
� There is limited scope for “borrowing strength” across countries, as each multiplier is specific to the dataset used
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSPDU PREVALENCE ESTIMATES (3)
� Implications for EMCDDA
� Differences in the methodologies adopted to estimate PDU are a problem when making comparisons between countries, or when estimating PDU across the EMCDDA 30 countries
� They are less problematic when monitoring changes over time within individual countries, as long as the methodology remains the same
� There exists a potential trade-off between adopting a common methodology across the EMCDDA 30, and the discontinuity that such a change may entail for a particular country
� There is limited scope to “borrow strength” across multiple countries, as each multiplier is highly specific to the base dataset being used
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSTREATMENT DATA (1)
� Centralisation
� Does not necessarily entail existence of a single integrated system of individual client records
� Most countries operate a single national reporting system in which pre-aggregated data are drawn together from different sub-systems
� The organisational structures of such sub-systems tend to reflect either organisational/institutional distinctions, or geographical region
� In the most basic approach, double-counting is eliminated at the level of individual treatment facilities
� More advanced systems eliminate double counting at the level of sub-systems
� Few countries have developed a process of client identification applied across the entire national system
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSTREATMENT DATA (2)
� Integration
� To date, most national reporting systems follow the reporting structure of TDI, but exclude GPs and low-threshold agencies from core datasets
� Not all treatment centres are included in counts and data collection may focus on larger treatment units only
� This can be corrected for by extrapolating to all facilities, taking account of their relative size
� This process of extrapolation might be improved upon using the facility surveys that are planned in EMCDDA countries
OBSERVATIONS FROM THE 2011 NATIONAL REPORTSTREATMENT DATA (3)
� Overcoming Double-Counting
� The most effective way to eliminate double-counting is to use client IDs
� Client IDs are widely applied within individual treatment facilities, and double-counting as a result of multiple treatment episodes within a given centre is largely eliminated from reported TDI data
� The introduction of client IDs across multiple facilities – generally using pseudonyms – remain the exception rather than rule
� Where studies exist on the overlap between sub-systems, these tend to relate to the broad TDI categories
� Overlaps between facility types as specified in the Generic Mapping System have not yet been reported
TOWARDS A METHODOLOGICAL TOOLKIT (1)
� Double Counting as a Result of Multiple Service Use
TOWARDS A METHODOLOGICAL TOOLKIT (2)
� Overcoming Double Counting
� The most accurate and flexible way of tackling the methodological challenge of multiple service use involves the use of personal identifiers
� The anonymity of service users has to be protected by using special identification codes that can only be linked with individuals by a “trusted third party”
� The additional information provided by personal identifiers can, at least in theory, be used to identify overlaps between services and to count the number of interventions received by an individual
� Whilst technically possible, “pseudonomisation” is IT intensive, technically demanding and can generate additional difficulties in terms of data access and analysis, particularly if these are not planned from the outset
TOWARDS A METHODOLOGICAL TOOLKIT (3)
� Implementing the Use of Client IDs
� Decision at the aggregate level (EMCDDA countries)
� Decision at national level
� Achieving agreement/participation of treatment providers
� Tendering and commissioning of “Trusted Third Party” (TTP)
� Development and distribution of client software
� Implementation at level of treatment facility
� Collation of data and data aggregation
� Statistical analysis of data records at national level
� Reporting back to EMCDDA (using TDI/Generic Mapping System)
� EMCDDA 30 overall comparative analysis
TOWARDS A METHODOLOGICAL TOOLKIT (4)
� The Alternative: A Survey of Service Users
� A census of treatment providers could be used as sampling frame
� A stratified sample of treatment providers would be extracted
� A sample of service users would then be carried out
� Survey instruments would inquire about use of services and treatments received over previous year
� Results could be generalised to the total population of people in treatment
� The survey would provide reliable estimates of overlaps – multiple episodes and multiple services use
TOWARDS A METHODOLOGICAL TOOLKIT (4)
� A Synthesis: Mixed Methods Approach
� The calculation of overlaps requires either system-wide client IDs or a survey of service users
� Either approach would be adequate and it is not necessary for all EMCDDA countries to apply the same method
� Results can be used even if a minority of countries provide data on overlaps between facility types specified in the Generic Mapping System
� Results from individual countries may be extrapolated to “similar” countries or adapted using additional assumptions or models
� This “agenda” has the potential to yield considerable improvements in EMCDDA-wide estimates of the number of people in drug treatment
� Other benefits include policy-relevant insights into similarities/differences across countries and regions and over time
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