International Review of Surveillance and Control of Workplace Exposures: NOHSAC Technical Report 5
2.4 Data Collection, Analysis and Presentation
At the commencement of the project, a survey and data collection instrument was designed to seek pertinent information from each source about each surveillance system identified as being relevant to the project. As a minimum, the instrument captured the basic information and contents of each system, the costs of the surveillance system, the internal and external uses and aims of the system, and the future of the surveillance system. The instrument was used to collect information by either:
- completion by a research assistant during telephone conversation(s) with system managers, i.e., a structured interview
- partial completion by a research assistant during telephone conversation(s) with system managers and partial completion based on formal or informal information sources
- completion by system managers, or
- partial completion by system managers and partial completion by a research assistant during telephone conversation(s) or based on other formal or informal information sources.
The survey instrument is reproduced in Appendix 1.
For each surveillance system (and controls) identified in the review and about which sufficient information was collected, a description and evaluation of each was prepared and is presented in tabular format in section 4.0 of this report.
The information included in the tables is directly drawn from completed questionnaires, published literature, websites and conversations with system managers. In some cases, questionnaire responses are similar to text available in the public domain because respondents entered web-based information into questionnaires, which they thought was the most useful and comprehensive response.
2.4.1 Characteristics of effective systems
For the purposes of assessing the respective surveillance systems, factors that characterised successful systems were identified. The Centers for Disease Control and Prevention (CDC) website contains versions of documents which look at the evaluation of public health (injury/disease) surveillance systems generally, however, the publication makes mention of several key attributes that system designers or evaluators need to keep in mind during those processes. Many of these attributes seem applicable and can be adapted to describe work environment surveillance systems:
- Useful – Provides knowledge and information which influences risk control and other strategic initiatives designed to prevent injury and illness from workplace exposure.
- Simple – Simplicity in structure and ease of operation.
- Flexible – Adaptable to changing information and operating conditions both specific to the system and also to the work environment.
- Acceptable – Willingness of people and organisations to contribute to the system and to support its operation to ensure longevity as an appropriate system.
- Sensitive – Able to detect the appropriate information and to monitor changes over time in appropriate depth for the indicators of interest, based on the current state of the country and its associated workforce.
- Appropriate specificity – A level of confidence in the accuracy of data collected and in its ability to direct intervention into the most important and most needed areas.
- Representative – The system accurately reflects the level of exposure in the population; areas under surveillance are appropriately covered such that analysis, comparisons and any generalisations can be made.
- Timely in its overall operation – This refers to the co-ordination mentioned earlier regarding flow of data being made available for the system and being entered into the system, reports or information flowing from the data, and the appropriate policy, strategy and risk control mechanisms being initiated in a timely manner.
- Operated with appropriate resources – This refers to both human and monetary resources.
Other characteristics that arose during the formal and informal literature reviews and field work:[2,3]
- Standard data formats for individual systems to ease the issues associated with later information integration.
- Mechanisms that allow a flow of information through the chain of research and surveillance, policy development, intervention and information on the impact of interventions, in a structured and informative manner. The design of the Danish Surveillance System appears to have accounted for such.
- Efficiency in cost, flexibility and sensitivity to changes in working life structure.
- Mechanisms for removal of superfluous data.
- Supports discovery of emerging problems.
- Ability to detect changes in “noisy” patterns of results.
- Has accounted for information from operators of similar systems during design.
- Has accounted for information from those who will be providing data to the system.
- Pilot studies to identify deficiencies/issues in operation before full undertaking.
- Uniform definitions of indicators or measurements.
- Continuous or repeated data collection.
- Ability to compare across countries, perhaps according to socioeconomic structure.
- Ability to adapt to changes in the structure of the owner organisation.