H. Data Collection
Distinguishing between the terms "data" and "information" is important and useful. Data is simply a collection of words, numbers, and other characters with a structure. Information is "useful or applicable data." Data becomes information when it is useful, meaningful, relevant, and understandable to particular people at particular times and places and for particular purposes. What is information to one person can simply be useless data to another.
1. Data Collection Considerations
The following considerations are important in assessment data collection.
The Need for Accuracy. The information must agree with the reality it represents. The data on which it is based must be accurate and reliable.
The Need To Eliminate Bias. Consider the source of the data. Biases may be linked to the interviewer, respondent, recollection accuracy, time, seasons, culture, gender, and the instrument or measurement used for data collection. Biases may be minimized through triangulation, whereby a broad perspective is captured through inquiry among many stakeholders.
Ethical Considerations. Adhere to a high standard of ethics when soliciting data from stakeholders. Ethical practices include honesty and transparency, nonattribution, sensitivity to gender and cultural norms/taboos, and when possible, feedback on how the information provided was used.
The Need for Timeliness and Adequate Frequency. Information must be produced as and when needed. The frequency of data collection and reporting must match the rate of change in the situation being assessed.
The Question of Availability of and Access to Information. The way in which data is collected or the access to the data can affect the way the data is routed, who it reaches, and where its flow may be blocked.
2. Data Collection Methods
A range of data collection methods is available. The following list outlines some of the most common ways of collecting data in emergencies.
Automatic Initial Self-Assessment and Local Assessment by Key Elements in the System. For example, the staffs of "life-line" systems. This initial assessment can involve preplanned damage reporting by civil authorities and military units.
Visual Inspection and Interviews by Specialists. Methods can include flyovers, surveillance by special point-assessment teams (including preplanned visits), and sample surveys to achieve rapid appraisal of area damage.
Sample Surveying of Specific Characteristics of Affected Populations by Specialist Teams. Well-conducted surveys have a number of advantages, not least of which is the relative confidence that may be attached to data collected using formal statistical sampling methods. Several different types of sample surveys are available.
- Simple random sampling. Every member of the target population is equally likely to be selected, and the selection of a particular member of the target population has no effect on the other selections.
- Systematic random sampling. Every 5th or 10th member on a numbered list is chosen. Results may be inaccurate if the lists are structured in a biased manner).
- Stratified random sampling. The population is divided into categories (or strata); members from each category are then selected by simple or systematic random sampling and then combined to give an overall sample.
- Cluster sampling. The sample is restricted to a limited number of geographical areas, known as "clusters"; for each geographical area chosen, a sample is selected by simple or random sampling. Subsamples are then combined to get an overall sample.
- "Sentinel" surveillance. This method is used widely in emergency health monitoring, where professional staff establish a reporting system that detects early signs of particular problems at specific sites. The method can be applied to a variety of other problems where early warning is particularly important.
- Critical sector assessments by specialist. This involves technical inspections and assessments by experts. This type of sampling is required in such sectors as health and nutrition, food, water supply, electric power, and other infrastructure systems. Critical sector assessments may be compiled from reports by specialists of these systems or by visits by external specialist teams.
- Continuing surveillance by regular "polling" visits. This method of systematic information-gathering visits to key sites is a technique that is well developed in epidemiological surveillance of casualty care requirements and emergent health problems.
- Continuing surveillance by routine reporting. As the situation develops, it will be especially useful if routine reporting systems can be adapted and used to develop a comprehensive picture of events.
- Interviews with key informants. These include interviews of those in government and PVOs/NGOs/IOs and within particular groups of affected people, local officials, local community leaders, and (especially in food and displacement emergencies) with leaders of groups of displaced people.