Home 
Contact 
Profile 
Videos 
Dr Omar Hasan Kasule Sr.
MB ChB (MUK), MPH (Harvard) DrPH (Harvard)
Professor (Epidemiology and Bioethics)
Faculty of Medicine, King Fahd Medical City
WEB: http://omarkasule.tripod.com
Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010
TABLE OF CONTENTS
Pretest PAGE 3
Key Concepts In Health Care Delivery PAGE 4
Primary Health Care Delivery PAGE 7
Program Evaluation: General Concepts PAGE
Program Evaluation: Examples PAGE 10
Quality Assurance In Health Care Delivery Services PAGE 15
PRETEST
1. The following statements are true about community diagnosis
A. Community diagnosis is computation of rates of various diseases in the community using vital statistical data
B. Community diagnosis is necessary for planning public health interventions
C. A cross-sectional study is carried out in community diagnosis
D. The views of the target population are irrelevant in the process of community diagnosis because they are generally ignorant of medical matters
B. Community diagnosis describes the health status of a population with no concern about the underlying causative factors
2. The following statements are true about primary health care
A. Primary health care was defined at a conference in Alma Ata convened by the World Health Organization in 1978
B. Primary health care refers to essential health services that are universally acceptable to the target population
C. Primary health care services do not require any participation of the target population except as consumers
D. The content of primary health care services must be the same for all different communities and different places in the same country
E. Primary health care refers to simple, cheap, unsophisticated services provided to the poor of developing countries
3. The following statements are true about health promotion
A. Health promotion was defined in 1986 by the Ottawa Charter as a process of enabling people to increase control over and improve their health.
B. Health promotion is another term for disease prevention.
C. The individual has no role in health promotion, it all depends on the government.
D. Health promotion is provided in a primary health care setting.
E. Exercise and good diet are examples of health promotion.
Presented at a Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010 by Dr Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard) DrPH (Harvard) Professor (Epidemiology and Bioethics) Faculty of Medicine, King Fahd Medical City. Riyadh
1.0 DEFINITION OF A HEALTH CARE SYSTEM
The health care system can be described as resources, organization, and management
2.1 GENERAL DESCRIPTION OF A HEALTH CARE SYSTEM: The health care system is described using the following attributes: availability, adequacy, accessibility, acceptability, appropriateness, assessibility, accountability, completeness, comprehensiveness, and continuity.
2.2 COMPONENTS OF A HEALTH CARE SYSTEM: A health care system consists of institutions, human resources, information systems, finance, management, and organization, environmental support, and service delivery.
2.3 FACTORS OF A HEALTH CARE SYSTEM: The factors that determine the nature of a health care system are demographic, cultural, social, and economic. The official policy may be favor private, public, or mixed health care. Political ideology explains variations in health care systems. In capitalist countries like the US and the Philippines Canada , Japan , Australia , and Peru UK , Scandinavian countries, and Sri Lanka Cuba and China
6.0 HEALTH CARE PERSONNEL
Health care personnel are classified as independent providers, limited care providers, nurses, allied health professionals, and public health professionals. Independent providers are physicians practicing allopathic medicine in addition to practitioners of osteopathy, chiropractic, acupuncture, naturopathy, homeopathy, and naparopathy. Limited care providers provided a limited and very specialized range of services: dentists, optometrists, podiatrists, and psychologists. Nurses are LPN, LVN, and RN. Allied health professionals include dietitians, occupational therapists, radiographers, medical technologists, medical record keepers, medical laboratory technicians, and audiologists. Public health personnel are involved in preventive medicine activities such as health education, environmental sanitation, and occupational safety. Physician supply and distribution is affected by economic factors. Solution of problem of physician mal-distribution is not easy.
7.0 FINANCIAL MANAGEMENT
7.1 Cost: Costs may be fixed or variable. Regression analysis is used to separate fixed from variable costs. Costs may be direct or indirect. Cost and revenue centers must be identified. Cost allocation to various cost centers may not always be easy or straightforward.
7.2 Cash flow management is very important because cash is the king since it pays bills. Financial managers are risk averse. An organization may have to shut down if cash flow is negative. The basic accounting identity shown on the balance sheet is assets = liabilities + owner’s equity. Assets may be current or fixed. They may be tangible or non-tangible. The income statement shows profits, losses, revenues, and expenses. Net income = cash inflow – cash outflow. In accounting documentation debits are on the left-hand side and credits are on the right-hand side. Debits must equal credits. In accrual accounting revenue is recorded at the time that the service is performed and expenses are recorded at the time that they are incurred. Cash accounting records revenues and expenses at the time that cash is received or is paid out. Cash flow management is easier when accrual accounting is used.
7.3 Budgeting: Budgeting can be bottom-up or top-down. Budgeting may be incremental or may be zero-based. The budget may be fixed or variable. An organization has a cash budget and a capital budget. It also has a revenue budget and an expense budget.
Presented at a Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010 by Dr Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard) DrPH (Harvard) Professor (Epidemiology and Bioethics) Faculty of Medicine, King Fahd Medical City. Riyadh
1.0 DEFINITION AND SCOPE
1.1 History: a conference held in Alma Ata in 1978 formulated the concept of primary health care under the slogan of health for all by the year 2000. From available data the slogan has not been fulfilled but many strides have been made in the past 20 years towards the target
1.2 Definition: Primary health care (PHC) was defined by the World Health Organization in 1978 as essential health services universally accessible to individuals and families in the community by means acceptable to them through their full participation and at a cost that the community and the country can afford. It forms an integral part both of the country's health system of which it is the nucleus and the overall social and economic development. WHO’s slogan ‘Health for All by 2000’.
1.3 Entry: Primary health care is the frontline or point of entry of an individual into the health care system. It is centered on the individual and not the organ system or disease. It is provided at physician offices, clinics, and other patient facilities.
1.4 Content of PHC: PHC is a comprehensive care for common diseases including prevention, screening, diagnosis, and treatment. The content of PHC varies from place to place. In rich and developed countries, PHC may be very sophisticated medical procedures. In poorer countries, it may be simple and rudimentary. What is important is to make sure that PHC is relevant to local needs and is affordable by the community concerned.
1.5 Community participation: The local community must participate in the formulation of PHC. PHC must conform to their culture and local circumstances.
2.1 Eight elements WHO declared that PHC rests on 8 elements: health education, food supply and proper nutrition, safe water and basic sanitation, maternal and child health services including family planning, immunization against major infectious diseases, prevention and control of locally endemic diseases, appropriate treatment of common diseases and injuries, and provision of essential drugs.
2.2 Health education are learning activities that enable individuals to voluntarily make decisions, change behavior in order to enhance health.
2.9 Health protection and Preventive services: Health protection includes accident prevention, occupational safety and health, environmental health, food and drug safety, and oral health Preventive services include Maternal and Child Health, Screening, Clinical Preventive Services.
3.0 NEEDS ASSESSMENT
A distinction must be made among three closely related terms: need, want, and demand. Need is an elusive concept. It is conceived differently by the population and the planners. Need assessment is determining the gap between the ‘is’ and the ‘ought’. Service needs are real needs as assessed by health professionals. Service wants or service demands are perceived by the community. Data for needs assessment is of two kinds: service needs and service demands or wants. Data on service needs is provided from epidemiologic data, health data, health risk appraisals, information from stakeholders, and literature review. Data on service demands is obtained by consulting the target community, consulting opinion leaders, a survey of the target population, and observation of the target population. Needs assessment proceeds in 5 steps: determining present health status, assessing the environment, identifying and prioritizing existing programs, assessing service deficits in light of existing programs, dealing with the problems, and validating the needs.
4.0 COMMUNITY HEALTH PROFILE
4.1 Overall health status is assessed using mortality statistics, life expectancy, years of potential life lost (YPLL), Disability Adjusted Life years (DALY), and results of Nutritional and Health Surveys. The health profile should also be studied for specific segments.
4.2 The health status of infants and children is assessed using the infant mortality rate (IMR) and 1-4 year mortality rate.
4.3 The health status of adolescents and young adults (ages 15-24) is more difficult to assess using a few indices. Mortality in this age group is more among males and is due to motor vehicle accidents. This age group has behaviors and life style choices that endanger good health: drug abuse, tobacco use etc
4.4 The health status of adults is assessed using mortality. The leading causes of adult mortality are cancer, heart disease, stroke, injuries, liver disease, chronic lung disease, homicide, HIV, and diabetes mellitus. Health behaviors and lifestyle choices that impact good health negatively are smoking, poor nutrition, lack of exercise, and neglect of screening for disease.
4.5 The health status of seniors >65 years is assessed using morality and morbidity. Mortality is falling, life expectancy is increasing but issues remain about quality of life. The main cause of mortality are cancer, stroke, COPD, pneumonia, and influenza. Morbidity is due to chronic conditions (HT, OA, CHD, and DM) or impairments (hearing, cataracts, orthopedic). Alcohol, tobacco, and obesity are important behavioral problems.
5.0 THE DISADVANTAGED
Community diagnosis must be sensitive to the special needs of disadvantaged minorities that live in poverty. Poverty can be defined in absolute terms and in relative terms. Economic inequalities translate into health inequalities. The disadvantaged are one parent families, the unemployed, the sick or injured, the disabled or handicapped, the elderly, the immigrants, and racial or ethnic minorities.
6.0 ROLE OF EPIDEMIOLOGY IN PRIMARY HEALTH CARE
Epidemiologic methods are used in the assessment of subjective and objective aspects of health. Epidemiologic data on morbidity and mortality is used in planning and evaluating health programs. Epidemiologic studies, observational and experimental, are used to define specific etiological relations. Epidemiological tools are used in screening, investigation, and control of disease. Clinical epidemiology guides clinical practice. Epidemiological methods are used in health services to plan, implement, and evaluate health interventions. Evaluation consists of cost-benefit, cost-efficiency, and cost-effectiveness analyses.
Presented at a Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010 by Dr Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard) DrPH (Harvard) Professor (Epidemiology and Bioethics) Faculty of Medicine, King Fahd Medical City. Riyadh
1.0 DEFINITION
Program evaluation is study of effectiveness, outcomes, efficiency, goals, and impact. Evaluation may be uses clinical assessment, health services research, health policy analysis, and epidemiology. Health plans are assessed based on the basis of accessibility, satisfaction, technical quality of care, efficiency and cost-effectiveness, and financial stability.
2.0 TERMINOLOGY
A project has a start and an end and is carried out only once. A project goes through the the phases of concept.
A program is carried out repetitively with no start or end.
Process evaluation: is evaluation of the processes involved in health care without reference to the output. Efficient processes normally lead to better output. There are cases in which the processes are efficient but the output is not as expected due to other factors that have to be taken into consideration.
Outcome evaluation focuses on results. The following are used as outcome measures: mortality, morbidity, patient satisfaction, quality of life, degree of disability or dependency, and any other specific end-points.
Evaluation may be described as qualitative evaluation or quantitative evaluation. Participatory evaluation has many advantages over non-participatory evaluation.
Performance criteria are set and records are analyzed to determine the proportion that meet the given the criteria. Data on performance is usually obtained from a sample.
Indicators used in evaluation may be sentinel indicators or rate-based indicators. Both process indicators and outcome indicators may be financial, clinical, or organizational.
Efficacy of drugs and treatment techniques can be tested in controlled experiments. These can be randomized trials, before and after comparisons, comparison of utilizers and non-utilizers, and case control studies.
Effectiveness involves testing effects in real life. Efficiency is computation of the cost-benefit ratio.
Access to care is a measure of how easy is it for patients to obtain care at a given facility. Use of services measures how many units of diagnostic or treatment services are used. Other terminology used in program evaluation is program intervention, program merits, program objectives, program activities, program outcomes, program impact, program expenses and costs.
4.0 COMPONENTS OF PROGRAM EVALUATION
Program evaluation starts with formulation of questions to be answered on demographics, activities, effectiveness, costs, and the general environment. The answers to questions provide the data on which the evaluation is based. Baseline and interim data may also be used in the evaluation. Question formulation is followed by setting standards, determining an evaluation methodology, collecting data, analyzing data, and preparing an evaluation report.
5.0 WHAT TO EVALUATE
Evaluation of health services in in three areas: structure, process, and outcome. Items to look at in structure include the physical plant, technical resources, human resources, lines of communication, and budget allocations. Process indicators include appointment systems, services provided, diagnostic tests done, preventive procedures, education classes, and referrals to other agencies. Items to look for in outcome evaluation are death and morbidity rates of various diseases and conditions, disabilities, discomfort and dissatisfaction of patients. (Page 332 John M Last: Public Health and Human Ecology 2nd edition Prentice Hall International Inc ? year).
6.0 EVALUATION STUDY DESIGN
Three study designs are used: pre and post assessment in one group, randomization into 2 or more groups, and use of a control group. Inclusion and exclusion criteria have to be defined.
7.0 DATA COLLECTION
Evaluation may be based on existing data or on freshly-collected data. Data for evaluation may be obtained from various sources: medical records, vital statistics, review of published and unpublished literature, surveys, tests of achievements, observations, interviews of patients and providers, physical examinations, and clinical scenarios. Medical records may be computer or paper medical records.
8.0 DATA ANALYSIS
Data scales used are qualitative (ordinal and nominal) and numerical (continuous and discrete). The student t test is used to analyze continuous data. The Chi-square is used to analyze discrete data. Meta -analysis can be used as super analysis of evaluation data.
Three methods are used for indicator analysis: data trends, threshold, and guidelines. Data trends, increasing or decreasing, point to consistent changes. A threshold may be set for an indicator beyond which further investigation and action are called for. Guidelines may be set in such a way that specific actions are taken if ind
Presented at a Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010 by Dr Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard) DrPH (Harvard) Professor (Epidemiology and Bioethics) Faculty of Medicine, King Fahd Medical City. Riyadh
1.0 ANALYSIS OF WAITING TIMES
1.1 Defining the problem: Waiting time is a waste of time to the patient. To the care provider it is an ind
1.2 Description of waiting times: Waiting times are random events. ‘Channels’ refers to the number of lines and servers refers to number of care providers. Balking is when a patient refuses to enter a line that is too long. Reneging is when a patient stays in the line for some time and finding it too long decides to leave. Batching is when several people usually members of the same family enter at the same time. Jockeying is changing from one line to another that is thought to be shorter.
1.3 Queuing Theory uses the Poisson distribution to describe arrivals and the exponential distribution to describe service times. The exponential is the inverse of the Po isson.
The Poisson distribution is represented as P(x) = λx e-λ / x! where P(x) = probability of exactly ‘x’ arrivals, x = actual number of arrivals in a specific time period, λ = mean arrival rate, and x! = x factorial.
The exponential distribution is represented as P(t) = 1 – e-µt where P(t) = probability of serving a given number of patients in time t, t = service time, e = 2.71828 and µ = mean service rate.
For a single server single line system (same as the appointments system), P0 = 1 – λ / µ, L = λ / (µ - λ), W = L/ λ, Lq = λ2, Wq = Lq / λ, Pw = λ/µ where λ =expected number of arrivals per time period (mean arrival rate) and µ = expected number of services possible per time period (mean service rate), and P0 = probability that server facility is idle, L = average number of patients in the system, W =average waiting time, Lq = average number of patients in the queue waiting for service, Wq = average time a patient spends in the queue waiting, Pw = probability that a patient must wait.
For a multiple server system, P0 = 1 / [{n=0Σn=s-1 1/n! (λ/µ)n }+{(1/s!) (λ/µ)s (sµ/sµ-λ), Lq = P0 . [(λ/µ)s+1] / [s.s!{(sµ) – λ)/sµ}2, and Pw = P0 . {1/s!} {λ/µ}s {sµ/(sµ-λ)} where P0 = probability that all servers are idle, s = number of servers, Lq = average number of patients in the queue, and Pw = probability that an arriving unit must wait.
Formulations are also available for multiple server single line systems and multiple server multiple line systems. A general rule in queuing theory is that on average the arrival rate must be less than the system service rate.
2.0 ANALYSIS OF CAPACITY
Excess capacity should be built into the system to respond to unexpected demands. Output is measured as service units, patient-days, clinic visits, and number of procedures. In some cases capacity cannot be measured accurately and the peak volume is used instead. The production frontier is a straight line if resources are plotted against volume of patients. The region below the line is production possibility and above the line is production impossibility. The capacity analysis model compares capacity with output. A change in resource mix may enhance the system’s efficiency without necessarily increasing the total resource outlay.
3.0 EVALUATION OF PROJECT IMPLEMENTATION
A project goes through the phases of concept, definition, implementation, and evaluation. A project may be simple or complex. Various methods of project management and control are also tools for evaluating the implementation. These include PERT, CPM, and GANTT charts. Program Evaluation Review Techniques (PERT) is a management support system or a management tool that enables a manager to evaluate and control a project. Before applying PERT the project must be broken up into its component parts, a process called work breakdown structure (WBS). PERT shows the start and end of each activity, the critical and non-essential activities, the immediate predecessor of each activity. Critical Path Method (CPM) is similar to PERT. The GANTT chart shows the status of various project activities. It however does not show the sequence of the activities. It is therefore difficult to tell which activities will precede which in the critical path.
4.0 FINANCIAL EVALUATION OF PROJECTS
Financial evaluation of a project involves computing the present value, the internal rate of return, and the adjusted rate of return. Discounting is used to determine the present value of money. The discount rate (alternatively called the cost of capital) is not easy. The best approach is to use the rate from the return (also called opportunity cost) from alternative low-risk investments (such as bank accounts, treasury bills, treasury bonds, and treasury notes). The internal rate of return is the actual return of the project. The adjusted rate of return is obtained after adjusting for market financial rates. Annuity is even cash flow every year like mortgage income. Annuities are of two types, ordinary and annuity due. Ordinary annuity is paid at the end of the period. Annuity due is paid at the start of the period. . Cash flow is critical to organizational survival. Nett cash flow = cash inflows (revenues) – cash outflows (expenses). Cash flow may be negative or positive. Future cash flows must be discounted in comparison with the present value of money. Depreciation is an expense that does not involve cash. The payback period is the time during which the investment can be recouped.
5.0 UTILIZATION REVIEW
Utilization review has three objectives: ascertainment that procedures are medically necessary, ascertainment that level of service intensity is appropriate, and ascertainment that the cost is appropriate. Review may be carried out pre-admission, during hospital stay (concurrent review), and retrospective review. The conflict between demand for higher quality and minimum costs arises in utilization review.
6.0 EVALUATION REPORT
The report must have an abstract or an executive summary. The contents of the report are the introduction, methods, results, discussion, and recommendations.
7.0 ROLE OF EPIDEMIOLOGY IN THE EVALUATION OF HEALTH CARE
Epidemiology provides basic data on which evaluations are based.
1006 QUALITY ASSURANCE in HEALTH CARE DELIVERY SERVICES
Presented at a Workshop On Health Research Priorities Organized By The Research Directorate Of The Ministry Of Health At Jeddah 5-7 June 2010 by Dr Omar Hasan Kasule Sr. MB ChB (MUK), MPH (Harvard) DrPH (Harvard) Professor (Epidemiology and Bioethics) Faculty of Medicine, King Fahd Medical City. Riyadh
1.0 OVER VIEW
1.1 Definitions
Quality assurance and peer review are control tools in the health care industry. Assessing quality of medical care by structure and outcome.
Quality assurance (QA) is formal and systematic identification, monitoring, and overcoming problems in health care delivery.
Quality improvement (QI) is a management philosophy to improve organizational performance.
Total Quality Management (TQM) is a participatory and systematic approach to planning and implementing continuous improvement in quality. The term audit is sometimes used to refer to quality review.
Benchmarking is establishing targets based on leading performance indicators of the industry concerned.
Quality is different from the perspective of the patient and that of the caregiver. The definition and measurement of quality are still a dilemma. Quality in consumer economics is easy to measure since it is based on consumer satisfaction. Quality in industry can be quantified easily and its determinants can be identified and can be incorporated into the worker training and service delivery systems. Quality in medicine is seen more as what is wrong and not what is right. Outcome measures of quality have the disadvantage that they are probabilistic with no consistent relation between health intervention and health outcome. The price of a health intervention can be measured but not its value. There is no consensus on what is appropriate intervention. Generally assessment of quality covers personnel, facilities, processes, and outcomes. An exact definition of quality of health services is elusive. It may be defined as maximizing patient well-being, improvement of life, or desired health outcomes. To avoid confusions, quality in any specific discussion must be defined empirically and contexually.
1.2 History
The concept has evolved through 3 stages: Quality control (QC) through Quality assurance (QA) to Quality improvement (QI). Wide-spread use of computers in hospitals has increased the need for and ability to carry out quality reviews since data is readily available. TQM started in ind
1.3 Purposes
QA is normally part of good clinical practice being a continuous monitoring tool to make sure that care given is up to expectation. It is also required in some situations of accreditation and even licensure
1.4 Principles
The 4 major principles of TQM are intrinsic motivation, review of systems (problems are in systems and not individuals, use of the scientific method (hence the involvement of epidemiology), and adult learning to change behavior in view of the findings of the quality process.
1.5 Common quality problems in health care
The common problems in medical quality are: insufficient knowledge, defect in the system, and different behavior and performance. Recording of the clinical data is the corner-stone of QA reviews. The QA reviewer can not attend all medical procedures and will have to rely on the records for evaluation. The records must be a faithful representation of what actually happened. Data problems are usually: incomplete data, inconsistent data, and data without record of time. Uniform reporting of data facilitates quality reviews.
1.6 Process of QA
Quality assurance involves planning, action, checking, action, and returning to planning. The processes of QA can be summarized by the mnemonic: FOCUS-PDCAE. Finding a process to improve. Organizing a team. Clarifying current knowledge. Understanding the process and causes of the problem. Selecting procedures to improve. Planning data collection & determining what data to collect. Data collection and analysis. Checking data to see opportunities for improvement. Acting to improve the process. Evaluation
2.0 QUALITY INDICATORS, CRITERIA and GUIDELINES
2.1 Quality indicators are mortality, morbidity, patient satisfaction, and various rates. The indicators must be assessed for validity, reliability (precision), and acceptability because of random and systematic errors.
2.2 Consensus guidelines must be developed for each clinical situation to be a bench-mark against which clinical performance can be evaluated. Good Clinical Practice (GCP) is a set of guidelines that have been developed and they undergo continuous revision. They are not a universal prescription since each situation will have to be treated differently. Clinical protocols are developed for dealing with specific diagnostic categories of specific procedures. Nursing guidelines or standards
3.0 METHODS and PROCEDURES of QA REVIEW
3.1 Types of QA reviews: QA review may be concurrent or retrospective. Concurrent review occurs when the reviewer attends and directly observes health care delivery such as attending a ward round, an operation, or an out-patient clinic. Retrospective review normally depends on review of records or interview of patients and health care providers. Quality review may be discipline specific (e.g. surgery or obstetrics) or site specific (heart, and lung).
3.2 The QA reviewers: The QA reviewers may be independent clinical auditors from outside or may be part of the health care team assigned the special function of QA. In most cases QA review by a committee gives best results. Many institutions train nurses to be QA reviewers and they report to the institutional or departmental QA committee. Peer review is when a person of persons of equivalent professional status carry out the review.
3.3 What is reviewed: QA in hospitals centers around review of the patient charts. The following records are reviewed: physician notes, nursing notes, pharmacy records, dental records, etc. Additional documents may be reviewed as necessary. Other aspects reviewed are morbidity and mortality figures, waiting times, the ratio between primary and secondary care. Physician performance is assessed based on knowledge and skills, observation, an clinical audit.
3.4 Method of review: The aim of QA review is to ascertain compliance with the given guidelines. If a deviation is found, it is documented as well as its surrounding circumstances. It is discussed at the departmental QA committee. The committee will suggest actions to be taken to alleviate the deficiency and map out an implementation plan.
3.5 Follow-up: The QA review process is cyclical. The QA reviewers must follow up on the recommendations of the QA committee and ascertain that they have been followed.
4.0 EPIDEMIOLOGICAL METHODS USED IN QA PROGRAMS
Epidemiology provides data and to provide comparison tools used in quality studies. It studies the impact of quality on health outcome by comparing rates (incidence, prevalence, and risk). It also deals with issues of validity and reliability in quality measurements. Data can be obtained from routinely collected data or from special studies (cohort, case control, and cross-sectional). For certain quality problems the usual methods of documenting a deficiency, discussing it, and suggesting solutions may not be suitable. Specific epidemiological studies are used to investigate the causative factors of the problem and to evaluate the impact of interventions. Case control, cross-sectional, cohort, randomized, and quasi experimental studies are used. A sampling plan is made. Variables to be investigated are selected. The reliability and validity of the instrument are determined. Data collection may be in person, by mail, or by telephone. Incidence, prevalence, odds ratio, and risk ration are epidemiological measures that can be used to describe QA phenomena