research: measurments (feel free to edit this set!)

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Consists of rules for assignment number
of objects to represent quantities of attributes
OR
Process of assigning numbers to variables

measurement

measurement rules x 3

under what conditions, what method, numeric values to be used

advantages to measurement x4

removes guess work from gathering info, can be independently verified by others (objectivity), produce precise info, language of communication

errors of measurement

instrument not accurate= degree of error

obtained score=

true score +/- error

these are problematic because they represent an unknown quantity and they are variable

errors of measurement

what contributes to errors of measurement

situational contaminants, transitory personal factors, response-set biases, Instrument format, Administration variations, Instrument clarity, Item sampling-errors

scores can be affected by the conditions under which they are produced

situational contaminants

scores of an individual
may be influenced by temporary personal states

transitory personal factors

number of relatively enduring
characteristics of the respondents that can interfere
with accurate measures of the target attribute.

response-set biases

alterations in the methods of collecting data from one subject to the next

administrative variations

if directions for obtaining measures are vague or poorly
understood, then scores may be affected

Instrument clarity

sometimes introduced as a result of the sampling of items used to measure an attribute

Item sampling-errors

technical characteristics of an instrument can influence the obtained measurement

Instrument format (example: open ended questions vs closed ended questions)

The degree of consistency with which an instrument measures the attribute it is
supposed to be measuring

reliability

characteristics of reliability x 3

stability, consistency,
dependability of a measuring tool

the less variation an instrument produces...

the higher its reliability

extent to which same results are obtained on repeated administrations of the
instrument

stability

administration of the same
test to a sample of individuals on two occasions
then compare the scores obtained
• Compute a reliability coefficient

Test-retest procedure

Looks for a relationship between two phenomena

Reliability coefficient

advantages of reliability x 3

- Test-retest method is easy
- Can be used with self- report, observational & physiologic
measures
- Used with traits that are relatively enduring such as personality,
abilities or physical attributes such as height

disadvantages of reliability

- Many traits do change over time- regardless of the measure eg
(behaviors, attitudes etc)
- Second administration may be influenced by memory of first
administration
- Subjects may change as a result of taking the test the first time
- Responses could be haphazard if subject is bored or impatient
with instrument

correlation of various items
within the instrument (homogeneity), measures the
same characteristic, Most widely used method for reliability, Requires only one test administration

Internal Consistency

- The items composing a test are split into two groups and scored independently
- Score on the two half-tests are used to compute a correlation coefficient

Split-half technique

advantages of Split-half technique

Easy to use, Eliminates most of disadvantages of test-retest

disadvantages of split-half technique

Reliability estimates can be obtained by using different splits (odd/even; first/second half)

Produce a reliability coefficient that can be interpreted as the other correlation coefficients, Yields values of 0 to 1.0

Chronbach's alpha or Kuder-Richardson
20 (KR 20)

why is Chronbach's alpha or Kuder-Richardson better than split-half technique

because it computes all possible splits to estimate homogeneity

Comparing two versions of same instrument or two observers (inter-rater reliability) measuring the same event

Equivalence

what is the goal of equivalence

Goal is to determine the consistency or equivalence of the instruments in yielding
measurements of the same traits in the same people

is estimated by having two
or more trained observers watching some event
simultaneously & independently recording the
relevant variables according to a predetermined
plan or coding system

Interrater reliability

how are the results of the Interrater reliability used?

Results are used to compute an index of equivalence or agreement. Can use a correlation coefficient to compare results

* Refers to the degree to which an instrument measures what it is supposed to be measuring.
(Accuracy of the measure)

Validity

o Whether the instrument looks as though it is measuring the appropriate critical variable (or construct).
o Not the strongest way to determine validity

Face Validity

o How well the instrument represents the characteristic to be assessed
o Used for affective measures (feeling, emotions, psychological traits) & cognitive measures (knowledge)
o Based on judgment of experts

Content Validity

o Must ask the question: "how representative are the questions on this test of the universe of all questions that might be asked on this topic?"

* Cognitive Scale

Emphasis is on establishing the relationship between the instrument and some other criteria, Criterion must be clear cut & objective

Criterion-Related validity

Criterion-Related validity examples

* For example: instrument to measure birth control use among sexually active teenage girls-criterion to compare it to may be subsequent premarital pregnancy
* Measure professionalism among nurses (attribute to be measured) to number of articles published (criterion)
* Measure effectiveness of nursing care to supervisory ratings of nurse

true or false: Criterion related validity is a relationship but also is a predictive relationship

true

o Degree to which an instrument can accurately forecast the future

Predictive validity

o Judgment is to the degree to which an instrument can accurately identify a difference in the present
o Use 2 instruments to measure the same concept

Concurrent validity

Method for indentifying clusters of related variables.
Procedure is used to identify and group together different measures of some underlying attribute

* Factor Analysis

each cluster is called a factor, what does this represent

* Represents a group of items that identify the same characteristic

true or false: Validity is never proven

true: its verified, supported by evidence

T or F: reliability and validity Are not totally independent qualities

True

T or F: A measuring device that is valid must be reliable

true

T or F: An instrument can be reliable without being valid

true

Beliefs that are held to be true but have not necessarily been proven OR A principle that is accepted as being true based on logic or reason, without proof

Assumptions

beliefs assumed to be true by a large percentage of society (all humans need love)

universal assumption

characteristics of assumptions

Derived from a theory of previous research (stress causes disease).
Specific to a certain research study (evidence of a fit between what the researcher believes can happen & the data produced)

T or F: Assumptions ARE NOT THE research question or hypothesis

true

Uncontrolled variables that may affect study results and limit the generalizability of the findings

limitations

• Limitations mentioned could include x3

* Sample deficiencies
* Design flaws
* Weaknesses in data collection

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