Measurement and Variables

Question 1

What do quantitative measurements do in research?

benefits?

Answer 1

• describe who the people in your study are
• provide precision in your description
• allow for comparisons

benefits:

• can be used for a diagnostic tool
• decided course of treatment
• differentiate btwn individuals and their needs
• key to communication across many disciplines

Question 2

constructs and operational definitions

Answer 2

construct: an idea you are trying to capture
ex: intelligence is an idea of how smart a person is

operational definitions: the frame of reference in which we understand the constructs

examples:

beauty (construct): physical appearance in regards to symmetry (OD)
speed (construct): distance covered in a period of time
disability (construct): ability to do something based solely on independence

Question 3

what are the scales of measurement

Answer 3

1. nominal: unordered category, does not mean one thing is better ex: blonde hair, black hair, no hair, green eyes, blue eyes
2. ordinal: ranked but not equivalent, distance btwn doesn’t mean much, but are in order ex: strongly agree, agree, somewhat agree, neutral, etc.
3. interval: equal distance btwn the variables/measurement points, no true zero
4. ratio: distance btwn measurements are equal but there is an absolute 0 ex: height and weight

Question 4

reliability of measurement

Answer 4

the degree that a measurement is consistent and error free

observed= true score + error

Question 5

standard error of measurement

Answer 5

used to give you some wiggle room because of the error factors

Question 6

systematic error vs random error

Answer 6

systematic: miscalibrated BUT it was consistently off for everyone so you can adjust for this
random: can NOT control for but with a large enough group of people it can be washed out

Question 7

what are some potential sources of measurement error

Answer 7

• participants
• scoring
• testing
• instrumentation

Question 8

how to establish reliability

Answer 8

• test-retest reliability
• alternate forms
• rater reliability
• internal consistency

Question 9

test-retest reliability

Answer 9

is what we are measuring consistent across time

Question 10

alternate forms

Answer 10

different forms of same test get same results/test for same thing

Question 11

rater reliability

Answer 11

intra: are you consistent with yourself
inter: consistency across different testers for same test

Question 12

internal consistency

Answer 12

are the questions within the assessment the same and do they get consistency

Question 13

measurement validity

Answer 13

the extent to which an instrument measures what it is supposed to measure

• a valid test is always reliable but a reliable test is not always valid

Question 14

types of validity

Answer 14

• face
• content
• criterion related
• concurrent
• predictive
• construct: convergent vs discriminant

Question 15

face validity

Answer 15

does it appear to measure what it is measuring

Question 16

content validity

Answer 16

each item of the measure seems to be measuring the construct

Question 17

criterion-related validity

Answer 17

is it equal to something that is already established

Question 18

concurrent validity

Answer 18

if you take two different IQ tests they should get similar responses, different measures of the same construct should yield similar results

Question 19

predictive validity

Answer 19

does it predict a future outcome, ex: IQ predicts academic achievement

Question 20

construct validity: convergent and discriminant

Answer 20

convergent: other measures of the construct is related to our test
discriminant: it doesn’t correlate with something that is opposite of it

Question 21

ecological validity

Answer 21

• is a reliable and valid measurement meaningful?
• Does the study reflect the real world or does it have real-world consequences?
• Do the findings generalize beyond the research procedure to the natural context?

ex: ACT, GRE of bad ecological validity

high ecological validity: quick and dirty assessment, vision test, BOT, ADOS, driving test

Question 22

what are variables?

Answer 22

• not a constraint
• free to VARY, can take on different values for different people, situations, cases etc.
• often assigned a letter X/Y

Question 23

independent vs dependent variable

Answer 23

IV: manipulated by the experimenter

DV: outcome measure

Question 24

attribute variable vs active variable

Answer 24

attribute: researcher cannot assign, ex: boy, girl, blue eyes, tall, short
active: can assign

Question 25

categorical/discrete variables vs. continuous variables

Answer 25

categorical/discrete: divide into categories

continuous: measure along a continuum