week 8 quantitative methods : measurement and sampling Flashcards
what do measurements do?
link data to concepts
why is studying measurement important?
helps understand the type of data collected, understanding appropriate methods and better research
what is conceptualization?
- understanding abstract concepts
a definition in abstract, theoretical terms
“the process of thinking through the various meanings of the concept”
EXAMPLE: “CRIMINALITY”
A study is interested in people’s “criminality”
what is conceptual definition and the operational definition
Conceptual definition
* “Non-sanctioned acts of violence against other members of society or their property”
Operational definition
* Counting a person’s number of criminal arrests from official records; OR
* Calculating the amount of time a person has spent in prison; OR
* Asking people whether they have committed crimes
what is operationalization?
development of research procedures that will give empirical observations
why are operational definitions important in research?
- force us to think carefully
- allow replication
- measureable
example * What is a conceptual definition of ethnicity?
* What is an operationalized definition of ethnicity?
conceptual : * Ethnic identity which refers to self-identification within a particular group
* Ethnic origin which refers to classification based on the ethnic group to which the individual’s ancestors belong
operational : Ethnic identity:
* The individual’s self-identification within specific ethnic groups Common survey question:
* “Please write down the term that best describes the ethnic character of your everyday home environment”
Ethnic origin:
* Used in many national surveys (National Population Health Survey, Canadian Community Health Survey).
* Country of birth
* Language
categorical vs continuous variables
continouous : you take an average and it has meaning : eg: age or blood pressure - changing
categorical variable : you measure and it has no meaning - average smoker
what are discrete variables?
- variable that can only take on a certain number of values
are categorical variables considered to be discrete variables?
yes! - only certain number of values
are the following categorical or continuous
1. age
2. achievement test : pass/fail
3. score on achievement test : 1-100
- continuous
- categorical
- continuous
what is the nominal level of measurement ?
- allows researchers to classify characteristics of study pop into categories
- least precise
- no math
whats an example of nominal measures
blood type - only one category per person
what is your occupation? - choose one
what is the ordinal level of measurement
- categories and categories can be ordered in a meaningful way
- rank accoringly to charactertistics and object posses
- mutally exlusive
what is an example of ordinal measurement?
SES
- low
-medium
- high
how would u describe your health?
- poor
-good
-excellent
highest level of schooling
- elementary
- high school
-university
what is the interval level of measuremnt?
- ranked in order and actual value between values has some meaning
- numbers have meaing but no true zero point eg:: tempature
what are ratio levels of measurement?
all the other charactertistics and also have an absolute zero point which represents absence
- fixed measuring units
example of ratio levels
- body weight
- zero kg = no weight
- person who is 20kg is twice as heavy as 10kg
what is each of the level of measurement for : John is 10 years old and Sam is 20 years old
1. nominal
2. ordinal
3. interval
4. ratio
- john is young and sam is old
- john is younger than sam
3.john is 10 years younger than sam - sam is twice as old as john
what is reliability
the ability of a measuring instrument to produce consistent results under similar conditions
what is test-retest reliability?
reliability across time
what is inter-rater reliability?
independent evaluations conducted by different individuals
what is parallel forms of reliability?
reliability across indicators (i.e., two versions of the same scale should yield nearly identical results)
what is internal consistency?
Whether different items on the same test correlate
Degree to which scales are correlated, made on the assumption that scales should measure a single construct