Words & Usage in Medical Writing

Words & Usage in Medical Writing

In medical writing its is common to get confused with words like amount vs level, ability vs capacity. Here is a quick guide to such words and their correct usage

In medical writing its is common to get confused with words like amount vs level, ability vs capacity. Here is a quick guide to such words and their correct usage

Written By: Dr Carole J

Last Updated on February 17, 2024

In science communication it is common to get confused with similar words or selecting words that are not apt. Here are some common words that researchers get confused when writing research papers or manuscripts.


1. Ability vs Capacity


  • Ability: The mental or physical power to do something, or skill in doing it.

Example: Optimal oxygen transport depends on the remarkable ability of hemoglobin to combine with oxygen.

  • Capacity: The full amount that something can hold, contain, or receive.

Example: The oxygen capacity of 1 g of hemoglobin is 1.39 ml of oxygen.

2. Accuracy vs Precision vs Reproducibility
  • Accuracy: The degree of conformity of a measurement to the known or true value of the quantity measured.

Example: The accuracy of the polygraphic method for estimating the efficiency of oxidative phosphorylation was checked by the conventional manometric technique.

  • Precision: The degree of refinement with which a measurement is made or reported.

Example: The value 3.43 shows greater precision than the value 3.4, but it is not necessarily more accurate.

  • Reproducibility: The degree to which related measurements, made under the same circumstances, can be duplicated.

Example: The reproducibility of the method, as analyzed in 18 series of sequential measurements in 12 dogs, was excellent.

3. Affect vs Effect
  • Affect (verb): To act on or influence.

Example: How smoking affects health is still a matter of concern to physicians.

  • Effect (noun): A resultant condition.

Example: We studied the effect of epinephrine on glucose kinetics in dogs.

4. Alternately vs Alternatively
  • Alternately: Following by turns: first one, then the other.

Example: The mice were alternately fed and deprived of food.

  • Alternatively: Involving a choice between two or more courses of action or possibilities.

Example: The dog's weight can be controlled by diet or, alternatively, by drugs.

5. Among vs Between
  • Among: In the midst of; used to express the relation of one thing to a group of many surrounding things.

Example: We found one intact test tube among the broken ones.

  • Between: Expresses the relation of two or more things as individuals.

Example: There were no significant differences between the three experimental groups.

6. Amount vs Concentration vs Content vs Level
  • Amount: The total bulk, or quantity, of that which is measured.

Example: The amount of DNA isolated from the left ventricle of the rats was 600 μg.

  • Concentration: The amount of a substance in a given amount of another substance; the strength or density of a solution.

Example: The concentration of DNA in the left ventricle of the rat is 1.5 μg/mg of tissue.

  • Content: The total amount of a substance in another substance.

Example: The ventricular content of DNA is 600 μg.

  • Level: Position along a vertical axis; relative position or rank on a scale; also used for amount, concentration, or content.

Example: 1) The chest was opened at the level of the fifth rib. 2) Cardiac output and heart rate did not increase above normoxic levels. 3) Blood sugar levels remained stable throughout the experiment.

7. Can vs May
  • Can: Denotes the power, or ability, to do something.

Example: Homogeneous cell lines of short duration can be achieved with cloning techniques.

  • May: Refers to possibility or to permission.

Example: This mechanism may also be the cause of the ozone effect noted in two other studies.

8. Continual vs Continuous
  • Continual: Intermittent, occurring at repeated intervals.

Example: The experiments were hampered by continual infections in the rat colony.

  • Continuous: Uninterrupted, unbroken continuity.

Example: The machine made a continuous hum.

9. Incidence vs Prevalence
  • Incidence: Number of cases developing per unit of population per unit of time.

    Example: The incidence of tuberculosis is 100 cases per 100,000 persons per year.

  • Prevalence: Number of cases existing per unit of population at a given time; the degree to which something occurs.

    Example: The prevalence of tuberculosis in the Bay Area is 300 cases per 100,000 persons.

10. Include vs Comprise vs Compose vs Consist Of