Home 
Contact 
Profile 
Videos 
Presentation to the Module I: Clinical Epidemiology at a Clinical Research Coordinator Course held on 5-9 January 2020 at Faculty of Medicine, King Fahad Medical City, Riyadh. by Professor Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard), DrPH (Harvard), Chairman of the KFMC IRB
KEYWORDS AND TERMS:
• Survey report
• Survey, Field Survey
• Survey, Health Surveys
• Survey, Morbidity Survey
• Survey, Nutrition Survey
DEFINITION AND OBJECTIVES
• DEFINITION: Surveys are observational studies that involve a large number of respondents than the usual sample. They supplement information from the census and vital statistics registration.
• OBJECTIVES OF SURVEYS: Measure of health and disease, Assessment of need, Assessment of the use of services, Assessment of the effectiveness of care.
• TYPES OF SURVEYS: Surveys can be census surveys covering the whole population or sample surveys covering selected samples. Either of these may be carried out as a mail survey, a telephone survey, a personal interview, or an observational survey.
HEALTH SURVEYS: PLANNING
• Literature survey.
• State the objectives: identify the problem being investigated. Determine the priority of the problem.
• Formulate a hypothesis.
• Define the population, Define the sampling frame, Define the size of the sample, and the method of sampling.
• Train investigators.
• Consider logistics: clearance, manpower, materials, and equipment (eg maps), finance, transport, communication, accommodation.
• Prepare and pre-test study questionnaire.
HEALTH SURVEYS: STUDY DESIGN
• Type of study: cross-sectional or longitudinal.
• Sampling unit: household is usually employed as a basic sampling unit.
• Sampling methods: simple random sampling, systematic sampling, stratified sampling, cluster sampling, multistage sampling.
• Sample size is n = Z2 p(1-p) / d2 where d is the precision usually set at 0.05 or 0.1. If n<0.1N, the formula for sample size becomes n = {Z2 p(1-p) / d2} / {n/(1 – n/N).
HEALTH SURVEYS: DATA COLLECTION
• Existing data
• Questionnaire
FEATURES OF A GOOD QUESTIONNAIRE
• Brief.
• Questions are clear with no ambiguities.
• Questions are not leading.
• The questions are in a logical order.
• Skip patterns are clear and are logical.
• The most important questions are at the start; sensitive questions are kept at the end.
• Closed questionnaire is preferred to the open one. The closed one must have categories for 'other' and 'i do not know' to take care of unexpected alternatives.
METHODS OF QUESTIONNAIRE ADMINISTRATION
• Postal,
• Telephone,
• Diaries,
• Interview.
OTHER METHODS OF DATA COLLECTION
• Physical examinations direct observation.
• Laboratory investigations.
DATA MANAGEMENT
• Item analysis for outliers
• Validation.
BIASES
• Observer bias
• Sampling bias
• Selection bias
• Response bias
• Dropout bias
• Memory bias
• Self-selection bias
• Lead time bias
USES OF THE SURVEY REPORT
• Communicate the findings.
• Application for funding.
ETHICAL ISSUES
• Sampling
• Confidentiality
• Research on human subjects
LEGAL CONSIDERATIONS IN FIELD SURVEYS
• Gaining access to subjects
• Protection of records
• Access to personal and medical records
• Trade and financial information
• Report contagious or dangerous diseases discovered during research
• Subpoena of epidemiologists to testify in court
• Taking compulsory measures: immunization, isolation, quarantine