23 Msmt and Instrumentation Flashcards
what is operationalization?
define how variable will be measured–make operational definition
when describing how measures taken, need to consider:
allow others judge adequacy and appropriateness, complete enough to let others replicate
objective measures are:
measures of quantities/qualities with equipment
what are subjective measures?
ratings or judgements of quantities and qualities by humans
examples of some quantities/qualities more suitable for subjective?
taste, degree of salt/sweet
observed value =
true value +/- error
desirable properties of msmt tools correspond to:
reliability, validity, practicability, applicability
ways to evaluate reliability?
test-retest, inter-observer, internal consistency
what is test retest?
make same test twice, correlate one with other, r>0.8 is good. If subjective, rate same variable twice
what is internal consistency?
extent to which results on diff items correlate when msmt tool/test has multiple items
if don’t have gold standard to determine validity, how to do this?
have some procedures to evaluate test validity, like compare diff methods
how to assess for validity?
content validity, sensitivity and specificity, predictive validity
what is content validity?
determine if all content has been tested
what is sensitivity?
proportion of ppl who test positive correctly
what is specificity?
proportion of ppl who test negative correctly
what is predictive validity?
ability of test to predict future values of it or another test
example of predictive validity
a rating scale x for selecting patients likely to respond to treatment, rating scale y evaluate effectiveness of treatment, determine correlation of x with y
measuring instruments/procedures developed w/ known lvls reliability and validity
standardized measures and tests
measure or categorize values of variable with ___ when only use numbers as labels and just have math of = or not =
nominal scales
rank ordering of values of a variable, can make statements about rank but not about size of difference
ordinal scales
continuous scale with defined intervals, with arbitrary rather than absolute zero point, enabling ID of equal intervals between msmt values
interval scales
zero is not arbitrary in this scale
ratio scales
these scales produce quantitative msmts
interval and ratio (higher scale allows more math ops)
type of scale determines type of ____ appropriate
statistic
