Transcript Document

GAP Toolkit 5
Training in basic drug abuse data management
and analysis
Training session 4
Types of question and types of
variable
Objectives
• Define a range of classifications for questions and
variables
• Discuss the use of levels of measurement in defining
variables in SPSS
Types of question
• Closed, open
• “Factual” and attitudinal
Closed questions
• The respondent selects from a list of mutually exclusive
and collectively exhaustive answers
• The answers are pre-coded
Example
• Has the patient been in treatment prior to this episode?
 Yes (1)
 No (0)
Example
• In the last 30 days, how many times (if any) have you
had 5 or more drinks in a row?
 None
1
2
 3-5
 6-9
 10 or more
“Other” Category
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An option on all but the simplest closed questions
Ensures the list of options are exhaustive
Allows flexibility in response
Post-coded rather than pre-coded
Example
• Type of centre:
 Specialized treatment centre
 Therapeutic community
 General hospital
 Psychiatric hospital/unit
 Other (specify): …………………………..
Dichotomous questions
• A subset of closed questions
• There are only two possible answers
• The answers are mutually exclusive and collectively
exhaustive
Examples
1. Gender:
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
Male
Female
2. Has the patient been in treatment prior to this episode?
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
Yes
No
Multiple-response questions
• The question allows more than one response
• The categories are not mutually exclusive
• Frequently, a grouping of dichotomous closed questions
Example
• Mode of ingestion of primary substance
(X all that apply):
 Swallow
 Smoke
 Snort
 Inject
 Other (specify): ……………………………….
Likert Scales
• A type of closed question
• Designed to measure attitudes
Example
• Do you disapprove of people doing each of the
following:
– Trying marijuana once or twice
 Don’t approve
 Disapprove
 Strongly disapprove
 Don’t know
– Smoking marijuana occasionally
• (options repeated)
Open questions
• There are no constraints on the respondent’s answer
• The answers cannot be predicted before the
questionnaires are presented
• The answers must be coded after the questionnaires
are collected
Examples
1.
2.
3.
Q30. Which new drugs or new patterns of use have
been reported?
Q13. Indicate primary substance of abuse, that is,
the most frequently used
Other (specify): ……………………..
Exercise: discussion
• Do Open or Closed questions appear more frequently in
the questionnaires used by your specific focal group?
Give reasons/possible explanations for these choices.
Response types
• Factual/attitudinal
• Direct/indirect
Types of variable
• Levels of measurement
• Types of variation
• Categorical vs. continuous
Levels of measurement
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Nominal
Ordinal
Interval
Ratio
Nominal
• The data describe an attribute
• The set of possible values the variable can contain
are mutually exclusive and collectively exhaustive
categories
• The categories cannot be objectively measured
against each other
Examples: nominal data
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Gender: male and female
Location: urban and rural
Religion: Christian, Hindu, Muslim, Jew
Race: white, black, coloured, mixed
Referral source: self, employer, court
Ordinal
• The data are broken into categories that can be
ranked
• It is not possible to quantify the difference between
the categories
Example: ordinal
• Level of education:
None
Primary
Secondary
Tertiary
Interval
• The data are measured on a continuous scale, not
simply ranked
• The units of measurement are constant
• There is no absolute 0
Example: interval
• Temperature:
– Fahrenheit or Celsius
• Measured on a continuous scale
• No absolute 0
Ratio
• The data are measured on a continuous scale, not
simply ranked
• The units of measurement are constant
• There is an absolute 0
Examples: ratio
• Age
• Income
• Temperature on the Kelvin Scale
Types of variation
• Nominal: equal categories
• Ordinal: ordered categories
• Interval and ratio: a continuous scale
Types of variation
• Qualitative: nominal
• Quantitative: interval and ratio
• Quantitative and qualitative: ordinal
Exercise:
identify the levels of measurement
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Name of treatment centre
Referral source
Gender
Age
Home language
Region of permanent
residence
• Highest level of education
completed
• Employment status
• Current marital status
• How old was the patient
when they first began using
drugs regularly?
Level of measurement in SPSS
• Nominal
• Ordinal
• Scale
Exercise: measure
• Return to Ex1.sav and set the level of measurement for
the variables ID, DRUG, AGE and COND
• Save the file
Summary
• Question types:
– Closed/Open
– Factual/Attitudinal
• Variable types:
– Levels of measurement
– Discrete
(categorical)/continuous
– Quantitative/qualitative