OPERATIONAL RESEARCH | NOTES ZA WIZARA | CMT LEVEL 6

Research:

Is a systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions. OR Is a careful and systematic process of inquiry to find answers to problem of interest

 

Health system:

A holistic system of health promotion, disease prevention and control, curative services, rehabilitation, regulatory and support systems put in place

It includes all public and private sectors, institutions which directly influence and support the health of people, embedded in the wider environmental-context


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NOTES ZA WIZARA | CMT LEVEL 6


1. Ethical Consideration: Code of conducts especially when dealing with human subjects. There a fundamental principals of research ethics:

i. Justice (be fair)

ii. Respect persons

iii. Beneficence (share benefits)

iv. Non mal-eficence (do not inflict harm)

2. Representative sampling: Research conclusion relies on representative sample

 

Characteristics of Research

The following are characteristics of research:

i. It originates with a question or problem.

ii. It demands a clear statement of the problem.

iii. It requires clear articulation of a goal, clear objectives and a plan

iv. It builds on existing data (using both positive and negative findings)

v. It follows a specific plan or procedures guided by specific problem, question, or hypothesis.

vi. It requires collection and interpretation of data.

vii. It is cyclical (helical) in nature.

 

Importance of Research

i. Research provides knowledge of the causes of diseases.

ii. Research contributes to developing cure and preventing diseases

iii. Helps promoting health for all.

 

Definition of Epidemiological studies

Epidemiological study is a study of disease distribution and its determinants in a population

Most of Epidemiological studies them form a main part of operational research

 

Categories of Epidemiological studies (2)

i. These studies complement each other and should not be considered as water-tight compartments.

ii. Descriptive study is limited to a description of occurrence of a disease in a population.

iii. An Analytical study goes further by analyzing relationship between health status and other variables.

iv. Experimental or intervention studies involve an active attempt to change a disease determinant or the progress of a disease, and are similar in design to experiment in other sciences.

 

Descriptive studies (1)

Is the first phase of an epidemiological investigation.

Concerned with distribution of disease or health-related characteristics in human populations and identifying the characteristics with which the disease in question seems to be associated

Useful in formulation of an aetiological hypothesis

Involves the following procedures:

a. Defining the population to be studied

b. Defining the disease under study

Describe the disease by:  

i. Time

ii. Place

iii. Person

 

Descriptive studies (2)

Cross-Sectional Study:  

Involves observation of some subset of a population of items all at the same time.

It assesses group's health status and exposure status simultaneously i.e a snapshot in which the health status and exposure are studied at the same time

Takes place at a single point in time

 

Advantages of Cross-Sectional Study:  

i. Is a snapshot i.e the researcher does not have to wait for the health outcome to occur or estimate what the level of exposure was likely to have been years ago.

ii. Useful for hypothesis formulation

Disadvantages of Cross-Sectional Study:  

i. Cause can not be inferred, because only current health and exposure are being studied.

ii. Can miss cases of short duration

 

These studies looks at the entire population to test the hypothesis

Used to determine:  

a. Whether or not a statistical association exists between a disease and a suspected factor;

b. If one exists, the strength of the association.

There are two main categories of observational study

a. Case-control studies

b. Cohort studies

 

This is a type of study design, used to identify factors that may contribute to a disease by comparing subjects who have the condition (the cases) with patients who do not have the condition but are otherwise similar (the controls).

In case- control study:

i. Both exposure and outcome (disease) have occurred before the start of the study

ii. Proceeds backwards from the effect to cause;

iii. It uses a control or comparison group to support or refute an inference/hypothesis

Has 4 basic steps:

i. Selection of cases and controls

ii. Matching cases and control

iii. Measurement of exposure,

iv. Analysis and interpretation

 

Case-Control studies (3)

Advantages of Case-control studies:

i. Is useful in establishing the association between exposure and diseases

ii. Can be used to study rare health outcomes

iii. Relatively less expensive as compared to cohort studies.

 

Disadvantages of Case-control studies:

i. Carries greater potential for bias.

ii. Does not allow for broader-based health assessments, because only one type of disease is studied at a time

iii. Is potentially affected by confounding factors that must be well controlled.

iv. Do not give any indication of the absolute risk of the factor in question.

 

Cohort studies (1)

Cohort is a group of people sharing a common characteristic or experience within a defined time period. E.g. People who are exposed to a particular vaccine or drug

In cohort study the study groups (with a known risk factor) is compared to another groups (without risk factor) and observed over a period of time to determine the occurrence of the problem to establish incidence of the studied disease

There are two types:

i. Prospective: the groups are defined before the study is done

ii. Retrospective: the groups are determined after data has been collected

Relative risk is used as the measurement of exposure in Prospective cohort study while Odds ratio is used in Prospective:

 

Case-Control studies (3)

Advantages of Case-control studies:

i. A desirable design because exposure precedes the health outcome, a condition necessary for causation

ii. Less subject to bias because exposure is evaluated before the health status is known.

 

Disadvantages of Case-control studies:

i. The cohort study is also time consuming and the most logistically difficult of all the studies.

ii. It is not suitable for rare conditions.

 

Experimental studies (1)

a. In experimental studies the investigator deliberately manipulates persons, objects or situations and measures the outcome of the manipulations.

 

b. It involves random assignment and techniques of blinding.

 

c. Experimental studies are used in more detailed phase, in which experiments are performed under more controlled conditions to test the hypotheses established by descriptive studies and observational studies to confirm association or efficacy.

 

Experimental studies (2)

They are of two types:

i. Clinical trials – randomised controlled trials

ii. Non randomised trial

iii. Clinical trial randomised but not controlled

iv. Community based interventions-randomised and controlled

v. Community based interventions –non randomised but controlled

Randomized control-studies has 6 basic steps

i. Drawing up a protocol

ii. Selecting reference and experimental populations

iii. Randomization

iv. Manipulation or intervention

v. Follow-up 6

vi. Assessment of outcome

Experimental studies are greatly limited by:

i. Ethical and legal considerations

ii. Difficulties involved in securing the cooperation of a large number of people.

 

Challenges in Conducting Epidemiological Studies

i. Recall bias

ii. Selection bias

iii. Confounding