Research Methodology

Review of Research Process

1. Identification of general problem/question

2. Literature review

3. Specify questions/hypothesis

4. Determination of design/methodology

5. Data collection

6. Data analysis/presentation

7. Interpretation of findings

• Based upon the idea of LOGICAL POSITIVISM

• there is singular reality with stable, social facts that are separate from the feelings and beliefs of individuals

Quantitative

• Based on CONSTRUCTIVISM

• Multiple realities that are socially constructed through individual and collective perceptions or views of the same situations

Qualitative

• Concern is with the understanding of social phenomenon from participant's perspective

• Requires researcher's participation

Qualitative

• Seeks to establish relationships and explain causes of changes in measured variables

• Goal of science is to explain and predict

Quantitative

Data Type in Qualitative

• Words

• Objects

• Pictures

• Observations

• Symbols

Data Type in Quantitative

• Number and Statistics

Quantitative research is also known as

• Priori or pre-established design

Use of emergent design utilizing constant comparison and revision

Qualitative research

• Descriptive

• Correlational

• Causal-comparative

• Experimental

Quantitative

• Ethnography

• Narrative

• Phenomenological

• Grounded theory

• Case study

Qualitative

• Used to reduced error, bias, and influence of extraneous variables

• Control of bias is through design

Experimental or correlational designs

• Helps readers understand the multiple perspectives of the situation by persons studied

• Subjectivity in data analysis and interpretation is acknowledged

Ethnography

Detachment from study in order to avoid bias

Quantitative

Immersion in the situation and phenomenon being studied

Qualitative

Obtained through the use of measurements and statistics

Quantitative

Provided by detailed description of phenomenon

Qualitative

Results replicated by others

Quantitative

Extension of understanding by others

Qualitative

Who, what where, when

Quantitative

Why, how

Qualitative

Match with outcomes about knowledge and comprehension

Quantitative

Match with outcomes about application, analysis, synthesis, evaluate

Qualitative

• May be generalized to greater population with larger samples

• Easily replicated

Quantitative

• Seeks to explain and understand

• Ability to capture elusive evidence of student learning and development

Qualitative

Qualitative research uses _ reasoning

INDUCTIVE

• Obeservation or experiment > generalizations > paradigm or theory

Quantitative research uses _ reasoning

DEDUCTIVE

• Paradigm or theory > predictions > experiment or observations

Epidemiological Studies

Hierarchy of Research Designs

Hierarchy of Research Design

Study Design Sequence

Types of Quantitative Studies

• Descriptive

• True experimental

• Quasi-experimental

• Correlational

• Predictive

Research using Primary Data

• Cross-sectional

• Case control

• Cohort

• Randomized controlled trial

• Data gathered at one point in time

• Often used for surveys

• Cannot make interferences about causality

Cross-sectional study

• Start with the outcome

• Identify a samp,e with condition of interest

• Identify similar control group

• Look back to determine exposure

• Calculate the risk in cases and controls

• Cannot use established prevalence

Case Control study

• Start with identified group

• Determine exposurein everyone at the same time

• Follow the groupto determine who develops the outcome of interest

• Can be used to determine prevalence

• Association measured as relative risk (rate ratios)

Cohort Study

• Gold standard for determining associations

• Identify a group

• Randomly assigned individuals to exposure

• Only reliable way tocontrolfor confounding factors

Randomized controlled trial

Research using secondary data

• Literature review

• Systematic review

• Meta-analysis

• Analysis of existing data collected for another purpose

• Gather articles on a topic of interest

• Summarizethe findings

Literature review

• Gather articles using a pre-defined search strategy—may include unpublished studies

• Develop a priori objective criteria to evaluate quality of studies

• Summarize the quality of data and results

Systematic review

• Do a systematic review

• Obtain primary data if possible

• Summarize the data quantitatively

Meta-analysis

Fundamental assumption in Epidemiology and Health Research

• Disease doesnt occur in a vacuum

• Disease is not randomly distributed

• Uses a systematic approach to study the differences in disease distribution in subgroups

• Allows for study of causal and preventive factors

Epidemiology

Components of Epidemiology

• Disease frequency

• Distribution of disease

• Determinants of disease

Quantify disease

Disease frequency

• Who is getting disease?

• Where is disease occuring?

• When is disease occuring?

• Formulation of hypothesis concerning causaland preventive factors

Distribution of disease

• Hypothesis are tested using epidemiologic studies

Determinants of disease

Types of Primary Studies

• Descriptive studies

• Analytic studies

Describe occurence of outcome

Descriptive studies

Describe assocaition between exposure and outcome

Analytic studies

Research Designs

Timeframe of Studies

• Prospective

• Retrospective

Looks forward, looks to the future, examines future events, follows a condition into the futire

Prospective

To look back, looks back in timeto study events that have already occurred

Retrospective

Increasing Knowledge of Disease/Exposure

Develop hypothesis

Descriptive studies

Investigate its relationship to outcomes

Case Control Studies

Defines its meaning with exposures

Cohort studies

Test link experimentally

Clinical trials

Descriptive studies

• Case reports

• Case series

• Detailed presentation of a single case or handful of cases

• Generally reports a new or unique finding

Case Reports

• Experience of a group of patients with similar diagnosis

• Assesses prevalent disease

• Cases may be identified from a single or multiple sources

• Generally reporton new/unique condition

• May be only realistic design for rare disorders

Case series

Advantages of case series

• Useful for hypothesis generation

• Informative for very rare disease withfew established risk factors

• Characterizes averages for disorder

Disadvantages of case series

• Cannot study cause and effect

• Cannot assess disease frequency

One case of unusual findings

Case report

Multiple cases of findings

Case series

Population-based cases with denominator

Descriptive Epidemiology Study

Analytical Studies

• Observational

• Experimental

Experimental Studies

• Randomized Controlled Trials

• Community Trials

Observational Studies

• Group data

• Individual data

Group data

• Ecologic

Individual data

• Cross-sectional

• Cohort

• Case control

• Case crossover

• Treatment and exposures occur in a controlled environment

• Planned research designs

Experimental studies

• Most well known experimental designs

• Uses randomly assigned data

Clinical trials

Uses non-random data

Community trials

• Non-experimental

• No individual intervention

• Non-controlled environment

• Individuals can be observed prospectively, retrospectivelu or currently

Observational

• An observational design that surveys exposures and disease status at a single point in time (a cross-section of the population)

Cross-sectional studies

• Often used to study conditions that are relatively frequent with long duration of expression (non-fatal chronic conditions)

• Measures prevalence, not incidence

• Examples are community surveys

• Not suitable for studying highly fatal diseases or a disease with short duration of expression

Cross-sectional studies

Disadvantages of Cross-sectional studies

• Weakest observational design, (it measures prevalence, not incidence of disease)

• Prevalent cases are survivors

• The temporal sequence of exposure and effect may be difficult or impossible to determine

• Usually dont know when disease occured

• Rare events a problem

• Quickly emerging disease a problem

• Observational design comparing exposures in disease cases vs. healthy controls from same population

• Exposure data collected retrospectively

• Most feasible design where disease outcomes are rare

Case-Control Studies

Case-Control Studies

• Cases:

• Controls:

• Cases: Disaese

• Controls No disease

Case-Control Study

• Advantages

• Less expensive and time consuming

• Efficient for studying rare diseases

Case-Control Studies

• Disadvantages

• Inappropriate when disease outcome for a specific exposure is not jnown at start of study

• Exposure measurements taken after disease occurence

• Disease status can influence selection of subjects

• Study of “triggers” within an individual

• “Case and control component but information of both components will come from the same individual

Case-Crossover Studies

Hazard period which is thetime period right before the disease or event onset

Case component

Control period which is a specified time interval onther than the hazard period

Control component

• An observational design comparing individuals with a known risk factor or exposure with others without the risk factor or exposure

• Looking for a difference in the risk (incidence) of a disease over time

• Best observational design

• Data usually collected prospectivelt (some restrospective)

Cohort studies

Prospective Cohort Study

Retrospective Cohort Study

Advantages of Cohort Study

• Exposure status determined before disease detection

• Subjects selected before disease detection

• Can study several outcomes for each exposure

Disadvantages of Cohort Studies

• Expensiveand time-consuming

• Inefficient for rare diseases or diseaseswith long latency

• Lost to follow-up

• Investigator can control the exposure

• Akin to laboratory experiments except living populatio s are the subjects

• Generally involves random assignment to groups

• Clinical trials are the most well known exa,p,e

• The ultimate step in testinb causal hypothesis

Experimental

The subjects in the study who actually receive the treatment of interest

Treatment group

Subject of study who receive no treatment or a different treatment

Comparison group

• A design with subjects randomly assigned to treatment and comparison groups

• Provides most convincing evidence of relationship between exposure and effects

• Not possible to use to test effects of exposurez that are expected to be harmful for ethical reasons

Randomized Controlled Trials (RCT)

• Gold standard of research designs

• Provides most convincing evidence of relationships between exposure and effect

Randomized Controlled Trials

Disadvantages of Randomized Controlled Trials

• Very expensive

• Not appropriate to answer certain types of questions