Surveillance System Standards
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- Bu səhifədəki naviqasiya:
- 1.10 Data Analysis and Interpretation
- 1.11 Data Presentation and Reports
- 1.12 Surveillance System Implementation: Priorities, Timelines and Internal Communications
- 1.13 Resources
Class Guidelines Sampling method Should be clearly defined and may utilize any justifiable epidemiological method, (e.g., simple random, systematic, cluster, stratified, or complex sampling, convenience or probability sampling.) Includes methods for randomization and stratification. Includes information on the use of grids and transects where applicable. Includes discussion, where applicable, of level of detection (threshold), statistical level of confidence, diagnostic (field) sensitivity of the sampling, predictive value, and in some cases comparison to other methods of sampling. Outcome variables See standard 1.4, expected outcomes, products, decisions, and actions. Exposure/risk factor variables See standard 1.6, population characteristics. Should be clearly identified.
Choice of sampling method Justification is described including purpose of the sampling strategy (e.g., sampling for detection, census, prevalence determination, or disease trends.) Geographic extent of the study area under surveillance Sampling unit should contain a spatial context, (e.g., 2 randomly- selected samples per grid cell from 30 randomly-selected grid cells over a 400-sq.km. area, or 300 slaughter samples from abattoir that services 4 counties.) Time intervals and frequency of data collection Sampling rate or frequency and the response rate for survey data. Time the agent, or the pathological consequences, are first observed. Information regarding date/times of sample collection, date/times of diagnostics, and date/times of lab reporting. Methods of data collection and handling Refers to how raw data are gathered from the field, (e.g., face-to-face interviews, questionnaires, blood samples collected at sale or market, or necropsies of tissues from suspect animals.) Sample handling protocols, specimen chain-of-custody protocols, and cold chain measures should be available from laboratories. Sample degradation factors may be critical for some types of surveillance and should be addressed. Sources of potential bias Are determined to all possible extent prior to data collection. Trigger(s) for data collection Describe the event(s) that initiate data collection, such as the detection of an animal with clinical signs of disease. Data collection and transmittal From the field or laboratory may include Web-based data entry forms, e-mail, fax, postal mail, spreadsheets (sent by e-mail or fax), or entry into database software such as Oracle or Microsoft Access.
Surveillance and Data Systems for USDA/APHIS/VS 13 1.10 Data Analysis and Interpretation Standard: The methods used in summarizing, analyzing, and interpreting data are described in surveillance planning documents. In addition, the processes for analysis and interpretation are evident in reports and presentations.
a. The parties responsible for data summarization, analysis, and interpretation are identified. b. A scientifically sound and detailed plan of data analysis and interpretation is consistent with the purpose, objectives, and expected products for the surveillance system. c. Analytic methods are discussed in terms understood by VS professionals, including decision-makers whose expertise is not in a mathematical or analytical field. See standard 1.11. d. The data type collected is appropriate for the method(s) of analysis planned (e.g., categorical data may not be amenable to some methods of quantitative analysis.) e. Data analysis methodology is appropriate and supportable given the data sources, sampling methods, and type and quality of data. f. Data interpretation provides timely, relevant information that meets surveillance objectives (standard 1.3) and expected outcomes (standard 1.4).
g. Methods for dealing with inherent biases, confounders, missing records, and unequal sample sizes are addressed.
Supporting Information: Analysis: Outcomes of interest should have been determined prior to the collection of samples. General information is necessary for most analysis and may include descriptive statistics such as means, medians, modes, and standard deviations, as well as general epidemiological information including prevalence, incidence, and sampling duration. Of particular note to those developing surveillance plans and collecting data is consideration of population denominators. See standard 1.6, population characteristics.
More complex analysis, or analysis for unexpected purposes, may be conducted if the data are adequate; however, without advance planning, these needs may not be met.
Data interpretation is the process by which the analyst translates findings from the data into non- mathematical language useful for decision and policymakers. It should be transparent and describe the methods used to reach the options or conclusions presented. It also should be sensitive to the political environment, but the results not biased by political pressures. Where indicated, the interpretation of the analysis should provide options for decision-makers to consider. For example, if the analysis indicated a need for further surveillance, the analyst might provide parameters for different ways to achieve the goal along with strengths and weaknesses for each of them. Additionally, any assumptions that influenced the interpretation should be clearly articulated along with their ramifications and limitations. Finally, if possible, the sensitivity of any variable with exceptional influence should be discussed. For example, if the data from one area or set of samples have undue influence on the outcome, this influence should be discussed in the interpretation.
Surveillance and Data Systems for USDA/APHIS/VS 14
1.11 Data Presentation and Reports Standard: Data presentation and reporting procedures specify the content, frequency, audiences, and methods of data dissemination (e.g., mail, e-mail, fax, private Web site, public Web site) for reporting data obtained through the surveillance system.
a. The parties responsible for data presentation and reporting are identified. b. A plan for information dissemination is developed that assures communication to stakeholders and provides details on reporting format and frequency for distinct audiences so that communications are designed for maximal benefit for the target audiences. c. Statistical or mathematic outcomes are explained in terms that an audience of non-specialists is likely to understand, and in technical detail adequate for peer reviewers. d. Reports describing progress or conclusions are timely and relevant. e. Presentations and reports carefully consider data sensitivity issues. See Chapter 3 for data sensitivity issues and references to Federal regulations regarding confidentiality. f.
The implementation of data reporting procedures is evident from reports and other presentations and publications. g. Data reports and publications are consistent with the expected products for the surveillance system.
Supporting Information:
The dissemination of processed information derived from collected data to users and the linkage of targeted information to specific stakeholders completes the surveillance cycle. No surveillance system is complete unless it provides information that influences actions and decisions. Dissemination of surveillance data to those who need to know is a critical component of a surveillance system. Recipients should include those who prepare (or should prepare) reports, data collectors, and those with administrative or program planning and decision-making authority, as well as those involved with policy development.
A description of the surveillance plan and associated outcomes must include the intended audience and, for each audience, the communication format and frequency of reporting. Audiences include responsible parties within the surveillance system, as well as agency decision-makers and industry groups. In addition, the list of data sources should be considered as a specific audience. Careful planning is needed to target information and reports appropriately for maximal benefit.
The frequency of reports will depend upon the collection system used and the needs of users.
Reports should be timely and relevant. The frequency of reports will depend upon the collection system and the needs of users. Certainly, one must consider the impact and consequences of reporting data in varying stages of analysis and interpretation, but one must also weigh the impact and consequences of delaying reporting.
Chapter 3 provides additional information on data confidentiality standards.
Surveillance and Data Systems for USDA/APHIS/VS 15 1.12 Surveillance System Implementation: Priorities, Timelines and Internal Communications Standard: The relative priorities of the surveillance system and timeline for implementing various aspects of the system are described in surveillance and implementation planning documents, and include specific information to facilitate internal communications.
a. The timeline for implementing the surveillance system is consistent with the stated priorities for the system and there is logical order in implementing the surveillance system. b. Surveillance objectives have been prioritized and agreed upon by responsible parties. c. Internal communication pathways and documents are clear and understood by all responsible parties. d. All responsible persons or groups have received adequate training and have a clear understanding of their role in implementation.
The action steps needed to implement the various aspects of the surveillance system, and timelines, are described in the surveillance plan or associated implementation plan.
When surveillance objectives are met, information is provided to help determine actions and decisions. Some decisions and therefore some components of a surveillance system may have higher priority needs than others. The political environment and economic impacts associated with the disease may dictate the priority of implementation. Resource limitations and time constraints, as well as the need to pilot test various components of the system, may determine which components are addressed first. The objectives of the surveillance system should be carefully reviewed to prioritize implementation of various components of the system. To lend order to the prioritization process, stakeholders and responsible parties should agree on ranking criteria and their relative importance. The priorities of the agency, including those outlined in the VS Strategic Plan and NAHSS Strategic Plan, should be considered when prioritizing the surveillance objectives. See standard 1.3, surveillance objectives.
Responsible parties should develop appropriate documents for internal communications, including disease fact sheets, training manuals for all aspects of the surveillance system, and recording and reporting forms. In addition, internal communication plans and documents should be developed to ensure that all responsible parties understand the surveillance procedures and communication pathways, as well as the implementation action steps and timeline.
Communication with the IT application development team should occur early and often as surveillance moves from the planning stage to implementation. Responsible persons or groups charged with planning, implementation, and IT development should work cooperatively to develop clear data system requirements.
Training for data collection, data entry, sample collection, documentation, shipping of samples, and sample processing should be completed prior to commencement of each Surveillance and Data Systems for USDA/APHIS/VS 16
individual’s involvement in the surveillance activities. See Chapter 3.
Standard:
Assessment of necessary resources is prepared to evaluate the human and financial aspects of design, implementation, and maintenance of the surveillance system.
a. The budget for the surveillance system is consistent with its priorities, purposes, objectives, and expected outcomes. b. The budget for the surveillance system sufficiently ensures that the standards for data collection, management, and quality control may be achieved. c. Human resources and technical expertise are available to achieve the surveillance priorities, purposes, objectives, and expected outcomes. d. Budget information is routinely reviewed to evaluate alignment of the budget, the purpose and objectives of the system, and the system’s products to date.
Supporting Information: The budget includes direct costs.
Direct cost information includes any Federal funds appropriated to support other Federal or State agencies in the surveillance system. Information about use of budgeted funds – labor, rent, capital purchases, testing, indemnity, mail, supplies, vehicles, cleaning and disinfection costs, printing, etc. – must be collected.
Human resources are identified for the surveillance system. These may be new hires or redistributed from other duties.
1.14 Surveillance Plan Performance Metrics Standard: One or more objective measures of the surveillance system’s performance is included in the surveillance plan.
Metrics of performance should be part of a surveillance system and provide a means to measure the efficacy of the system.
The performance metrics should be consistent with the objectives and expected outcomes for the surveillance system and, ideally, provide a measure of the extent to which expected outcomes are achieved. The metrics should be quantifiable and the unit of measure may be addressed for budgeting needs. The population and geographic scope of each metric is identified. The metrics may be modified or replaced over time as needed to meet the needs of the system or changes in technology.
Surveillance and Data Systems for USDA/APHIS/VS 17 Note: While quantitative performance metrics are ideal, some subjective metrics may also provide useful information for measuring a system’s performance and these may be included as performance metrics.
Examples: Testing adequate to meet specified prevalence at a given level of confidence. This might be a number of samples or a number of surveillance points from a targeted strategy. Testing adequate to maintain a predetermined level of confidence. This might be equal to risk of disease introduction + the risk of pre-existing but not yet detectable disease. Testing adequate to detect disease in a specified number of days/weeks/months. Testing adequate to meet a specified sensitivity or specificity (i.e., probability of positive surveillance if disease exists or probability of negative surveillance if no disease exists).
Testing adequate to provide a negative predictive value (i.e., a measure of freedom from disease). This is the probability that no disease exists given negative surveillance.
A specified number of samples or observations in a given time, population, or location. 1.15 Surveillance System Evaluation Surveillance system evaluation is the collection and review of information undertaken to assess how well the surveillance system fulfills its stated objectives and meets accepted standards. The evaluation process identifies system strengths and areas for improvement. The evaluation findings are intended to facilitate the system’s role in a coordinated, integrated National Animal Health Surveillance System (NAHSS), consistent with the VS Strategic Plan.
Standard: The surveillance system is periodically evaluated to determine how effectively the system fulfills its stated objectives and meets surveillance system standards. The evaluation is conducted using the methods described in the Protocol for Evaluation of Surveillance Systems. (E-mail national.surveillance.unit@aphis.usda.gov. for more information.)
a. The purpose and outcome of the evaluation process are articulated and understood by responsible parties, stakeholders, and those involved in conducting the evaluation. b. Results of the evaluation are shared with responsible parties and stakeholders. c. Evaluation results provide meaningful information for program budgeting and setting program priorities. d. Evaluation results provide viable alternatives, improvements, or suggested solutions for components of the surveillance system that are deficient. e. The uses of past evaluation results are evident. Surveillance and Data Systems for USDA/APHIS/VS 18
Supporting Information: Surveillance systems should reflect national disease control and eradication priorities and promote the best use of public resources in the development of effective and efficient surveillance. National animal health surveillance systems have been developed in the past without standardized guidelines, designed at different times, and operated by different units within Veterinary Services (VS). VS field staff have been charged with implementing multiple systems with different objectives using different methods, terminology, and reporting forms and frequency. This may introduce extra costs and inefficiencies into these systems. Thus, there is a pressing need for regular evaluation of current animal health surveillance systems, especially given their complexity and the fact that most animal health data are collected under less than ideal circumstances. Also, in order to remain effective and useful, surveillance systems should adapt to changing situations such as new research findings regarding diagnostics, therapeutics or control procedures, significant changes in prevalence, legislation, global market pressures, or producer/public attitudes.
Surveillance systems should be evaluated regularly to ensure that they remain efficient, useful, and effective in order to meet their objectives. The evaluation process should include an assessment of whether the system’s objectives are being achieved and whether it is serving a useful function. The evaluation of surveillance systems should include recommendations for improving quality and efficiency, such as eliminating unnecessary duplication.
The 2001 Animal Health Safeguarding Review recommended that VS promote a more coordinated and integrated approach to the surveillance and control of infectious disease. The proposed evaluation protocol is an important tool to achieve this goal.
Surveillance and Data Systems for USDA/APHIS/VS 19 Document Outline
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