Lesson 8- Reliability, Validity & Control of Extraneous Variables Flashcards
Define reliability
Reliability- consistency of study- study repeated again & same results gained
What are the 2 general types of reliability?
1) Internal reliability
2) External reliability
What is internal reliability?
Internal Reliability- test & results gained consistent within itself- split-half technique assesses internal reliability of questionnaires e.g. questionnaire split in ½ & if pps score similarly both halves of questionnaire then questions measuring same factors & … internal reliability
What is external reliability?
External Reliability- test & results gained consistent over ⏰- test-retest method assesses external validity- e.g. study conducted once & again in future- if results similar then reliable
Define validity
Validity- study measuring what it intends to measure (fulfils aim of study)
What are the 4 types of validity?
1) External (ecological) Validity
2) Participant Validity
3) Temporal Validity
4) Internal Validity
Define external validity
External Validity- findings of study generalised to other settings
Define internal validity
Internal Validity- outcome of study direct result of manipulation of IV & ✖️ by EV- For study to have internal validity EV must be well controlled
Define participant validity
Participant Validity- results from pps used in study generalised to target population
Define temporal validity
Temporal Validity- results from study generalised to ppl in today’s modern society (over ⏰)
What are the 3 types of extraneous variables?
1) Participant variables
2) Experimenter variables
3) Situational variables
What are participant variables?
Participant Variables- characteristics of pps affect DV- appropriate experimental design helps to overcome this EV- e.g. Matched pairs & repeated measures design
- Repeated measures- same pps used-> order effects- resolve by counterbalancing (split pps)
What are experimenter variables?
Experimenter Variables- experimenter can affect DV- e.g. personality, appearance, conduct- resolved by standardisation- experimenter acts in similar way with all pps & follows script- same manner & tone
What are situational variables?
Situational Variables- factors in environment affect DV (e.g. time of day, noise etc.)- resolved by standardisation (all conditions, materials, instructions same for all pps)
What are investigator effects?
Investigator Effects- investigators influence results of study
What are the 2 ways in which investigator effects can occur?
1) Physical characteristics of investigator e.g. age etc- resolve using script- see ⬆️
2) If investigators know hypothesis -> bias in interpretation of results- overcome by double blind technique (neither pps nor investigator know aim of study-> ⬆️ valid data)
What are demand characteristics?
Demand Characteristics- EV- pps guess aim of research
What are the 4 ways in which pps show demand characteristics (what do pps do)?
1) Pps please experimenter by giving results they 🤔 experimenter wants
2) Pps annoy researcher by giving incorrect results (screw you effect)
3) Act unnaturally out of nervousness
4) Acting unnaturally out of social desirability
How do you overcome demand characteristics?
Overcome by single blind technique- pps ✖️ know aim of study … ✖️ influence 🏃♂- ⬆️ difficult in repeated measures design (same pps used)
