Levels of Measurement The mathematical precision with which

Levels of Measurement The mathematical precision with which the values of a variable can be expressed is the level of measurement. • The nominal (or categorical) level of measurement, which is qualitative, has no mathematical interpretation; • The quantitative levels of measurement—ordinal, interval, and ratio—are progressively more precise mathematically.

Nominal Measures The nominal level of measurement identifies variables whose values have no mathematical interpretation; they vary in kind or quality but not in amount. In terms of the variable “Occupation”, you can say that a lawyer is not equal to a nurse, but you cannot say that the “lawyer” is “more occupational” or “less occupational” than the nurse.

Ordinal Measures At this level, you specify only the order of the cases, in “greater than” and “less than” distinctions. A common ordinal measure used in social service agencies is client satisfaction. You may ask clients to indicate whether they are “very satisfied, ” “satisfied, ” dissatisfied, ” or “very dissatisfied” with a particular service. A client who responds “very satisfied” is clearly more satisfied than a client who responds “dissatisfied” – but not twice as satisfied or 2 units more satisfied.

Interval Measures At the interval level of measurement, numbers represent fixed measurement units but have no absolute zero point. Sunrise: 8: 05 am UV Index: 1, Minimal Sunset: 5: 12 pm Moonrise: 7: 56 pm Phase: Waning Gibbous Moonset: 9: 53 am Averages and Records for Jan 20 -12 4 -25 -16 Monday: Mainly sunny. High 4 F. Winds NW at 10 to 15 mph. Monday night: Clear to partly cloudy skies. Low -12 F. Winds WSW at 5 to 10 mph. °F °F °C °C Your text uses the example of temperatures measured with the Fahrenheit scale. The temperature can definitely go below zero, as indicated in this weather forecast for Fargo, ND.

Ratio Measures A ratio level of measurement represents fixed measuring units with an absolute zero point. Zero, in this situation, means absolutely no amount of whatever the variable indicates. On a ratio scale, 10 is two points higher than 8 and is also two times greater than 5. Ratio numbers can be added and subtracted, and because the numbers begin at an absolute zero point, they can also be multiplied and divided (so ratios can be formed between the numbers).

Level of Measurement Quiz time!

What is the level of measurement for the variable, “Number of Presidential Elections In Which Respondent Voted in Entire Life”, measured by the number the respondent reports? A. Nominal B. Ordinal C. Interval * D. Ratio

What is the level of measurement for the variable, “political ideology”, measured as “Very Conservative”, “Conservative”, “Moderate”, “Liberal” and “Very Liberal”? A. Nominal * B. Ordinal C. Interval D. Ratio

What is level of measurement for the variable “political party affiliation”, with values “Democrat”, “Independent”, “Republican” or “Green”? * A. Nominal B. Ordinal C. Interval D. Ratio

What is the level of measurement for the variable “Political Ideology Scale”, measured on a scale of 6 -24, where 6=Very Conservative and 24=Very Liberal? A. Nominal B. Ordinal * C. Interval D. Ratio

The Level of Measurement …is the mathematical precision with which the values of a variable can be expressed.