4. DATA COLLECTION AND SAMPLING METHODS

Data Collection Techniques (6)

• Observation

• Self-Report (Survey)

• True Experimental Studies

• Quasi-Experimental Studies

• Archival Research

• Sampling Techniques

Observation

• Documentation of perceptual and behavioral processes

  • (related to looking at, listening to, touching, tasting, or smelling something)

• No manipulations/high external validity

• Behaviors coded after observations recorded using software

Observation downside?

Time consuming!

Self-Report (Survey)

• A survey is a data collection tool used to gather information about
  individuals (mail, telephone, online, etc.)

• Can be used in conjunction with experiments or observational studies or on their own

• Important to use validated and reliable surveys

Self-Report (Survey) Tools?

Tools: Google Forms, Survey Monkey, and Qualtrics

Self-Report (Survey) Disadvantages?

• Sampling error: location and time of year can skew data

• Nonrespondents and low response rate

Open-ended questions (+)

• response thorough and unrestrained

Open-ended questions (-)

• answers may be difficult to read, interpret, or irrelevant

• difficult to code and summarize

• recent influence of ChatGPT on survey responses

Open-ended questions are best when?

• Exploratory research

• Focus groups

Close-ended questions (+)

easier to summarize

Close-ended questions (-)

not as comprehensive

Close-ended questions best when?

• Good understanding of content

• Theory testing

Develop Close-Ended Questions: Select Response Scales

• Nominal/categorical scales

  • Mutually exclusive groups (i.e., religious affiliation, gender, yes/no question)

• Ordinal scales

  • Rank order items (preference, importance, etc.)

• Interval scales (using Likert format)

  • Evaluative: Strongly agree – Strongly disagree

  • Frequency: Never – Always

  • Usually 5 or 7 point scales, but can use 4 or 6 to force choice

• Ratio Scales

  • # of times you took a nap in the past week; your weight

What to Avoid on Survey (4)

• No abbreviations/acronyms, jargon words (i.e. SES)

• No “double barreled” questions

  • Ex: Did the instructor provide a useful and interesting lecture?

• No absolute answer options (always or never)

• Avoid vagueness

Tips on Survey (3)

• Limit length & order survey items from MOST to least important

• Use pre-existing measures that have been validated

• Make sure to put demographics/priming questions at end

True Experimental Studies

An experiment is a controlled study in which the researcher attempts to understand cause-and-effect relationships. In a true experiment, the researcher controls

True Experimental Studies (2 components)

1. how subjects are assigned to groups and which treatments each group receives

   • (random assignment used)

2. experimental control reduces effect of confounding variables

Quasi-Experimental Studies (3)

• Similar to experimental designs, but lack the element of random
  assignment often because it is making use of pre-existing groups
  (experimental control somewhat involved)

• 3 components:

  • Single Group Pre-Test Post-Test

  • Nonequivalent Control Group Post-Test

  • Nonequivalent Control Group Pre-Test Post-Test

Single Group Pre-Test Post-Test

• Placebo effect possible

• Hard to generalize

Nonequivalent Control Group Post-Test

• Use naturally existing groups

• Problem with selection bias

Nonequivalent Control Group Pre-Test Post-Test

• Addresses selection bias problem. Group equivalence can be shown

• Can measure a true change in the dependent variable

Archival Research

• Rather than collecting your own data, you can use existing datasets when they contain your variables of interest

• Meta-Analysis: Run statistics using data from several existing publications

  • Combining results from different studies, in the hope of identifying patterns among study results and resolving sources of disagreement among those results

Sampling Techniques (2)

A subset of the population that is used to represent the entire population as a whole

• 2 components:

  • Probability Sampling

  • Non-Probability Sampling (no known chance of being selected)

Probability Sampling

• Simple Random Sample

• Systematic Random Sample

• Cluster sampling

• Stratified Random Sample

Non-Probability Sampling (no known chance of being selected)

• Convenience/haphazard sampling

• Snowball sampling

• Purposive sampling

• Quota sampling