This is an important advantage in applications sensitive to high incidence of missing data, such as construction of linkage maps35.
For very complicated data, such as the Western Australian Data Linkage System (WADLS), which was instigated in 1995 to link up to 40 years of data from over 30 collections for an historical population of 3.7 million, more linking methods were applied [ 5].
Calculated human concentrations can be integrated with toxicity data such as tissue concentrations, providing direct linkages to high throughput toxicity test data for screening-level risk assessment (Judson et al. 2011).
The inclusion of the Community Health Index in the recording of National Health Service (NHS) contacts in Scotland facilitates national linkage of data such as prescribing and healthcare utilisation.
Articles were excluded if they did not involve data linkage, such as a discussion of another form of health information technology; if they did not involve data, such as a commentary, letter or discussed a data linkage methodology without an empirical evaluation or if they presented a linkage project without comparing characteristics in matched and unmatched records.
Unfortunately the anonymous nature of the survey precluded linkage with surgical data, such as technique and other factors (bladder neck preservation, preservation of the neurovascular bundle inter alia) that have been shown to affect PPUI [ 2, 33].
Linkage overcame limitations of MHSC data, such as not tracking births, deaths, or moves out of Manitoba [ 21].
To date, data linkage has been conducted with specific health data (such as discharge coding from hospitalisations, immunisation records and pharmacy data) and there is also scope to link with education data.
These studies along with our results suggest the need for linkages of administrative to other types of data, such as pharmacy data (eg, antibiotics or inotropic use), to enhance the ascertainment of sepsis for surveillance purposes.
Linkage of PMTCT clinic data to community-level research data such as demographic surveillance systems (DSS) (10 sites in Africa with HIV sero-surveillance) (5, 6) could provide direct estimates of coverage with PMTCT services; currently a problematic statistic.
