Writing Tip

Use Progressive Inheritance in Units of Measurement

Difficulty Level: Basic

Recommendation: When you have a range of values, use progressive inheritance.

This tip is about units of measurement (%, kW, Hz, V, and so on). When you have a range of values, you don't have to spell out the unit of measurement for each number in the range. For example, let’s say you have a range of kilowatt hours (kWh). The minimum is 20 kWh, and the maximum is 30 kWh. Instead of expressing the range as “20 kWh to 30 kWh,” you can omit the unit of measurement from the first value, thus: 20 to 30 kWh (IEEE guidance disagrees, for your information, so if you are writing for an IEEE publication, please include the unit of measurement for both numbers). The first value inherits the unit of measurement of the second value. This works intuitively unless the metric prefix (k = 1000, M = 1,000,000, and so on) is different. For example, let’s say that the first value in a range is 100 kHz, and the second value is 5 GHz. The unit of measurement is identical (Hz), but the metric prefix is different (k versus G). In this case, the composite units of measurement are not identical. Therefore, you must spell out the unit of measurement in the first value: 100 kHz to 5 GHz.