Glossary

Secondary data are data that were already available before the current research project because they were originally collected for other investigation purposes. The NORAH Study on Health Risks is based, among other things, on secondary data – in this case on pseudonymized patient data from health insurance companies – which already existed before the NORAH Study.

In the sensitivity analyses the scientists carried out calculations separately for various sub-groups and then compared whether the estimate values found for the context differ substantially. If, for example, the connection is stronger for men than for women, this suggests that their blood pressure reacts more sensitively to noise.

In statistics, we speak of a significant result when the effect is very unlikely (usually less than five percent) to be coincidental. Significance can be reviewed by statistical calculations.

In sleep labs scientists can measure and observe the course of a person’s sleep and when he changes from one sleep phase to another. Almost all of the investigations carried out in sleep labs use polysomnography.

Socioeconomic status is an artificial term that attempts to summarize an individual's economic and social position in society. In the NORAH Study the socioeconomic status was determined with the aid of the so-called “Scheuch-Winkler Index”. This is calculated from the three factors: net income, education and qualification and professional position.

Sound is generated by vibrations of
a sound source.

This term is used by physicists to describe an individual event in which sound is generated.

This shortened expression usually refers to the sound pressure level – the physical quantity that describes the strength of the sound waves.

The sound pressure level is stated in decibels “dB (A)” and is a measure for the loudness. The decibel scale from 0 to 120 dB (A) reflects the range from the absolute threshold of hearing to the pain threshold.

In simplied terms, statistics speak of a significant effect when it is very unlikely (usually less than five percent) to be a random effect. Statistical significance is determined by calculations.

In order that a scientific study actually investigates what it is supposed to investigate, careful planning is necessary. Scientists refer to this as study design. It includes, among other things, the method of data acquisition as well as the type and scope of the data.

Blood pressure is usually recorded with two values. The higher value is the so-called systolic blood pressure. This measures the pressure in the arteries when the heart muscle contracts and presses the blood out of the heart chambers. The systolic blood pressure is, therefore, the pumping performance of the heart. The diastolic blood pressure is the phase in which the heart muscle relaxes and the heart chambers fill up with blood.