LEVELS OF MEASUREMENT

LEVEL	QUALITIES	EXAMPLE	WHAT YOU CAN SAY	WHAT YOU CAN'T SAY
Nominal (categories)	Assignment of labels. Classification. Inherent Qualitative data -Words. No mathematical meaning.	Gender (male, female) Voting Record (republican, democrat) Religion Types of Crime	Each observation belongs in its own category.	An observation represents “more' or “less” than another observation.
Ordinal (add order, rank)	Assignment of values along some underlying continuum. Opinion measures, degree of something being measured. Inherent Qualitative data.	Rank in college Order of finishing a race Strongly disagree to Strongly agree SES (Upper to Lower)	One observation is ranked above or below another. Can't infer absolute quantity nor that distance between any 2 levels is the same.	The amount that one variable is more or less than another.
Interval (add spacing of equal intervals)	Equal distances between points. Inherent Quantitative data.	Intelligence test scores Temperature Crime Rates	One score differs from another on some measure that has equally appearing intervals.	The amount of difference is an exact representation of differences on the variable being studied.
Ratio (add true zero)	Meaningful and non-arbitrary zero. Inherent Quantitative data.	Age Weight Income Exam Scores	One value is twice as much as another.	Not Much!

Sue is 20 years old and Mary is 40 years old. Simple statement regarding Sue's and Mary's ages that illustrates each of the levels of measurement.

Nominal: Sue is young and Mary is old

Ordinal: Sue is younger than Mary

Interval: Sue is 20 years younger than Mary

Ratio: Sue is twice as young as Mary

What is your Employment Status?

2. Work a few hours per week - less than 20

3. P/T - 20 to 29 hrs

4. ¾ time - 30 to 39 hours

5. F/T - 40 hrs or more

What is your Employment Status?

3. Student (not working)

5. Not employed (but not a student)

Region Region of interview

1. New England 5. South Atlantic 9. Pacific

2. Middle Atlantic 6. East South Central

3. East North Central 7. West South Central

4. West North Central 8. Mountain

Sex Sex of Respondent

Age Age (Determined by asking date of birth, actual ages recorded). Values reflect actual age.

Age3 Age variable recoded into thirds

Attend How often do you attend religious services? (recoded into four categories)

1. Less than once a year

2. Once a year through several times a year

3. About once a month through almost weekly

4. Every week or more

Sibs How many brothers and sisters did you have? Please count those born alive, but no longer

living, as well as those alive now. Also include stepbrothers and stepsisters, and children

adopted by your parents.

Values reflect actual number of siblings

SIBS3 SIBS, number of siblings, recoded into thirds

PartyID Generally speaking, do you usually think of yourself as a:

4. Other, please specify _______________

Polviews I'm going to show you a 7 pt.scale on which the political views that people might hold are

arranged from extremely liberal to extremely conservative. Where would you place yourself?

1. Extremely liberal 5. slightly conservative

2. liberal 6. conservative

3. slightly liberal 7. extremely conservative

4. moderate, middle of the road 8. Missing, don't know

9. Missing, no answer

Childs How many children have you ever had? Please count all that were born alive at any time

(including any you had from a previous marriage).

0 to 7 Actual number (e.g. 3 means 3 children)

Income In which of the following groups did your total family income, from all sources, fall last

year before taxes, that is?

1. Under $1,000 9. 10,000 to 14,999

2. 1,000 to 2,999 10. 15,000 to 19,999

3. 3,000 to 3,999 11. 20,000 to 24,999

4. 4,000 to 4,999 12. 25,000 or over

5. 5,000 to 5,999 13. Refused

6. 6,000 to 6,999 14. Missing, don't know

7. 7,000 to 7,999 15. Missing, no answer

RealInc Family income in constant dollars

RealInc RealInc variable recoded into thirds