Sole-variable

A 'sole-variable' refers to a factor or element within a given context that is deliberately isolated and manipulated by a researcher, experimenter, or analyst to observe its effect on other factors or outcomes. It represents the independent variable in a study, the one intentionally changed or controlled to test a specific hypothesis. The primary function of a sole-variable is to establish a causal relationship. The effects of manipulating the sole-variable are then observed in the dependent variable(s), thus allowing one to conclude that the dependent variable(s) depend on the manipulation of the sole-variable. This is in contrast to multiple variables or control variables, which need to be accounted for and kept constant in such experiments.

Sole-variable meaning with examples

• In a study examining plant growth, the amount of sunlight a plant receives is the sole-variable, while water, soil, and plant type are controlled. The experimenter adjusts sunlight exposure and measures how this impacts plant height and leaf count over time. This isolates the sunlight's effect. This careful management is designed to show a clear correlation.
• A marketing team tests different website headline variations to increase click-through rates. Each headline is the sole-variable in this A/B test. All other factors, such as website design and time of day for promotion are kept consistent. The team tracks which headline generates the most clicks, allowing for a direct comparison of each one.
• A researcher studying the impact of a new drug on blood pressure might use the drug dosage as the sole-variable. They give varying doses to different groups, ensuring other factors (age, diet, health history) are as similar as possible. The change in blood pressure becomes the dependent variable measured, reflecting the impact of the drug dosage.
• In a cooking experiment to study the effect of oven temperature on cookie texture, the oven temperature acts as the sole-variable. Ingredients and baking time are constant. Varying the temperature allows the experimenter to isolate its impact on the cookies' crispness, density and overall texture. The effect on each becomes measurable.
• An economist studying the effect of interest rates on inflation will identify interest rates as the sole-variable to change. They’ll gather information on the economic situation, which could then provide data that indicates relationships in the long-term. The results help to define how much inflation is caused by interest rate adjustments.