When production is dependent upon measurements, it is vital to make sure the measurements are accurate; however, measurement error is unavoidable. It is important to understand the causes of error so that one can minimize the possibility. This article will discuss the three main categories of measurement error: systematic errors, random errors and human errors.
Systematic errors occur due to a fault in the measuring device and are separated into 3 subcategories: instrumental, environmental and theoretical.
Instrumental errors occur when there is a defect with the measuring device. Environmental errors occur due to external conditions such as pressure, humidity and temperature, and theoretical errors are caused by simplification of the model system.
To reduce systematic errors, make sure the equipment is in good working condition, the environment is controlled, and the standards used are applicable.
Random errors are caused by sudden changes in experimental conditions. They are random and often unavoidable. You can see the effects of these errors when the least significant digit changes through out multiple readings.
Random errors may be unavoidable, but they can be minimized by taking multiple readings and averaging the results.
When humans are reading and recording the results, there will always be human error. Observational errors are due to wrong observations or readings. Parallax errors are due to the angle at which one reads and records measurements. Interpolation rounding errors occur when the reading falls between two lines on an analog device.
To reduce these human errors, make sure your equipment is up to date and to record the results at eye level.
Measurement error is bound to happen. But now that you know what to look for, errors can be minimized. Grand Rapids Metrology can help you determine if there needs to be a process adjustment to minimize and control measurement error.