Quantitative evidence

Quantitative evidence is a type of data that can be counted, measured and expressed using numbers. It is often collected through structured methods such as surveys or experiments.
This type of evidence is often used in science, including human biology, because it allows for precise measurements and statistical analysis.
In human biology, examples of quantitative evidence might include measurements such as blood pressure readings, heart rate, body mass index (BMI), or the number of cells in a certain amount of blood.

Quantitative evidence is typically gathered using structured research methods. These are methods with prespecified plans that can be replicated easily.
Techniques such as surveys and questionnaires may be used to gather quantitative evidence about things like lifestyle factors, symptoms, or behaviours.
More direct measurements such as blood tests, scans, or physical examinations are used to gather quantitative evidence about a person’s physical health.

Quantitative evidence can be analysed using statistical methods. These tend to involve mathematical calculations and operations.
Calculations, for example, could include working out means, medians, and modes for data sets, or calculating percentages and rate changes.
Graphs, charts, and tables are often used to visually present and interpret quantitative evidence.

When evaluating quantitative evidence, consider its validity and reliability. Valid evidence accurately measures what it is intended to measure, while reliable evidence can be replicated with the same results.
Quantitative evidence may also be evaluated for biases, where the method of data collection or processing favours a particular outcome.
The strength of the evidence is determined by the size of the sample and the method of collection. Strong evidence typically comes from a larger, randomised sample collected in a controlled manner.

Once analysed, quantitative evidence can contribute to the scientific understanding of human biology. It can help identify relationships, causations, and trends that may be key to developing treatments, interventions or public health guidelines.
However, quantitative evidence should not be interpreted in isolation. It is often important to complement it with qualitative evidence to ensure a comprehensive understanding of an issue or phenomenon.