Research Methodology and Design

Planning and Process of Research

• Formulate a problem to address a research question
• Select a research design to guide the study
• Define the population and sample, with the sample being a representative portion of the population
• Identify the target population, including groups of people, objects, etc.
• Establish a sampling frame to define the population
• Select measurement variables that are relevant to the research problem, reliable, and sensitive
• Identify instruments for measuring variables, and validate them for the specific population
• Collect data, using quality control methods to ensure accuracy
• Analyze data, interpret findings, and disseminate the results

Factors to Consider When Selecting a Measure

• Purpose: determine the research question being addressed
• Public vs. Private: consider the level of sensitivity required
• Direct vs. Indirect: decide whether to measure the construct directly or indirectly
• Objective vs. Subjective: choose whether to focus on what is or what is believed to be
• Standardized vs. Customized: select between standardized measures for comparisons or customized measures for specific populations
• Individual vs. Collective: decide whether to measure individual or group characteristics
• Performance-Oriented vs. Self-Report: choose between measuring performance or self-reported data
• Cognitive vs. Affective: focus on intellectual functioning or emotions/feelings
• Psychomotor: assess motor skills and dexterity
• Verbal vs. Nonverbal: decide whether to use written/spoken language or non-language based methods

The Nature of Measurement

• Measurement: assigning numbers to objects or events according to rules
• Data: collected measurements
• Data points: individual measurements
• Data set: a group of data points
• Variables: traits or characteristics that can be measured
• Quantitative variables: vary in amount and can be measured in units
• Qualitative variables: vary in kind and are not measured in units
• Discrete variables: have a limited number of values with no values between points
• Continuous variables: have an infinite number of values with values between points
• Levels of Measurement: including nominal, ordinal, interval, and ratio scales

Scales and Indices

• Scales: instruments that measure variables
• Indices: combine multiple variables to create a more complex measure

Types of Measurement

• Measurement Error: the difference between the true score and the observed score
• Systematic Error: predictable error
• Random Error: unpredictable error
• Reliability: the consistency of measurement
• Validity: the accuracy of measurement, including content, criterion-related, and construct validity
• Sensitivity: the ability of a measure to detect changes in the variable
• Specificity: the ability of a measure to detect changes in only the intended variable