1. Revision Sampling error
generally decreases as the sample size increases .
depends on the size of the population under study.
depends on the variability of the characteristic of interest in the population.
can be accounted for and reduced by an appropriate sample plan.

2. Data Kinds of information obtained from research participants, e.g.
Demographic info
Scores
Responses to questions
Essays
Grade-point-averages
Performance logs (sports)
Anecdotal records

3. Definition Instrument = the device used to collect data
Instrumentation = the whole process of preparing to collect data; involves
Selection or design of instrument(s)
Procedures and conditions under which the instrument(s) will be administered

4. Questions you would HAVE to ask…
Where will the data be collected? (location)
When will the data be collected? (time)
How often are the data to be collected? (frequency)
Who is to collect the data? (administration)
These are equally important as obtaining a ‘good’ instrument…!
Location, time, frequency, and administration are affected by the kind(s) of instrument to be used…!

5. Obtaining information
Researcher instruments (tally sheet, field notes)
Subject instruments (weekly spelling test, questionnaire, daily log)
Informant instruments (rating scale, anecdotal records, interview schedule)

6. 4 major ways to collect research data:
Administer a standardized instrument
Administer a self-developed instrument
Record naturally occurring events (observations in a classroom)
Using already available data set (G.P.A., etc.)

7. Constructing your own instrument…problems?
Not easy
‘good’ instrument takes lots of time to develop
Skills? Money? Energy?

8. Use already existing instruments
Alternative?
Use already existing instruments 

9. Examples of data collection instruments
Activity
List as many instruments that you already know (used or heard about)
Turn to your neighbor
Pair of pairs

10. Rating Scales Making judgment about a behavior or a product
Rating = observation + judgment
Observation = check the existence or non-existence of something
Behavior rating scales
Numerical rating scale
Graphic rating scale
Product rating scales (reports, maps, charts, diagrams, drawings, notebooks essays, etc.)

11. Interview Schedules Set of questions to be answered by subjects
Oral (written or recorded)
Clarification possible
Takes longer time
Inhibition (researcher’s presence)
Structured interviews - the questions and their sequence, is predefined (systematic) – clear goals
Unstructured interview - more free; interviewee develops the themes proposed by the interviewer – exploration of emotions, etc. (Rogerian counseling)
Semi-structured interviews – mixture of both
Open-ended questions
Closed-ended questions

12. Tally sheets
To record the frequency of behaviors, activities, or remarks

13. Performance Checklists
List of behaviors that make up a certain type of performance
Used to determine whether or not an individual behaves in a certain way when asked to complete a particular task

14. Anecdotal records
A record of observed behaviors written down in the form of anecdotes (short story)
No set format
Must be specific, factual and avoid evaluative, interpretive, and overly generalized remarks
Must use concrete descriptive statements

15. Questionnaires Save time and energy 
No way of clarifying answers/responses 
Selection items - Multiple choice, true-false, matching, or interpretive questions
Supply items – short answer, essay

16. Self-checklists
Subjects asked to study a list and place a mark opposite characteristics they possess or the activities in which they have engaged for a particular length of time

17. Attitude Scales Likert scale – commonly used attitude scale
Semantic deferential – measure a subject’s attitude toward a particular concept
Pictorial attitude scale

18. Personality (or character) inventories
Minnesota Multiphasic Personality Inventory
IPAT Anxiety Scale
Kuder Preference Record

19. Achievement Tests
Measure an individual’s knowledge or skill in a given area or subject

20. Aptitude Tests
Intended to measure an individual’s potential to achieve in a given area

21. Performance Tests
Measure an individual’s performance on a particular task
E.g. typing, driving, etc.

22. Projective Devices
Instrument with a vague stimuli that allows individuals to project their interests, preferences, anxieties, prejudices, needs, et.
No ‘right’ or ‘wrong’ answers
No clear-cut answer of any sort
Wide variety of response possible
E.g.
Rorschach Ink Blot Test
Thematic Apperception Test (TAT)

23. Sociometric Devices Ask individuals to rate their peers in some ways
E.g.
Sociogram – visual representation, usually by means of arrows, of the choices people make about other individuals with whom they interact
Group play – assigning roles to different individuals in a group play – to illustrate individuals’ interpersonal relationships

24. Measurement Scales
Nominal scales – assign numbers to different categories to show difference
Ordinal scales – order data in some way (high to low; least to most) – relative standing - ranking
Interval scales – characteristics of 1 & 2 plus distances between points on the scale are equal
Ratio scales – characteristics of 1, 2, & 3 plus a true ‘zero’ point

25. So what?
Questions:
Which of these four provides the least information?
Which of these four provides maximum amount of information?
How does the knowledge about different scales of measurement affect your research? (which part of research?)

26. Validity and Reliability
Think in terms of ‘the purpose/truthfulness of tests’ and the ‘consistency’ with which the purpose is fulfilled/met
Validity and Reliability
Neither Valid
nor Reliable
Reliable but not Valid
Fairly Valid but
not very Reliable
Valid & Reliable

27. Validity (truthfulness)

28. Reliability (consistency)