Program in Physical Therapy Clinical Measurement: Standards, Referents, and “Normal” Keith R. Lohse, PhD, PStat Program in Physical Therapy, Department of Neurology

Flashcards covering measurement concepts, data types, natural constants, criterion- vs norm-referenced values, and examples from the lecture.

What is measurement?

The comparison of a value to a standard; data are the result of measurement.

What are data in the context of measurement?

The results of measurement used to describe a sample and infer about the population or patient.

What is nominal data?

Qualitative labels indicating differences that are qualitative.

What is ordinal data?

Quantitative differences with ranking, but no fixed intervals.

What is interval data?

Fixed intervals between values but no true zero point.

What is ratio data?

Fixed intervals with a true zero, allowing absence of a quality to be represented.

Why are natural constants important for standard units?

They provide stable, universal definitions not dependent on arbitrary rulers or places.

How is the meter defined?

By the path traveled by light in a vacuum (speed of light).

How is the second defined?

Based on cesium-133 atom transitions used in atomic clocks.

What is the status of the kilogram definition (as of 2019)?

Defined by a natural constant rather than an artifact; previously linked to the international standard kilogram.

What is criterion-referenced measurement?

Measures based on natural criteria (e.g., forces, blood pressure) or other, non-norm-based criteria.

What are normative values?

Norms that indicate how a person compares to a population.

What is a key issue with normative references?

Generalizability across birth height/weight norms, countries, and time.

In the Olive example, what is a criterion-based measurement?

Olive's weight of 7.2 kg.

In the Olive example, why is Olive a normative assessment?

Because describing 'small' as a norm-based classification represents normative judgment.

What is the benefit of setting informative norms?

Norms can be used to assess health, function, or dysfunction when references are appropriate.

What must be examined when using normative judgments?

The reference used and whether it is appropriate for the context.

What is the recap of the lecture?

Difference between criterion-referenced and norm-referenced measurements; impact of natural constants; importance of appropriate references for normative judgments.

What were early measurements sometimes based on, and why is that flawed?

Regional or arbitrary definitions based on rulers or commodities; they lack stability and consistency.

Examples of natural constants used to define standard units?

Distance: the meter (speed of light); Time: the second (cesium transitions); Mass: the kilogram (natural constant).