Accuracy

Accuracy only applies to sensors that are supposed to be calibrated. For calibrated sensors of a particular make/model, the output is supposed to relate to some physical quantities regardless of the individual sensor. For example, if a type of temperature sensor is supposed to generate pulses that are proportional to temperature (say 1ms per $^oK$), all samples of this type of sensor should output a pulse of 273ms in water that is about to freeze.

Unless you are using a calibrated sensor (such as one of those expensive laser-based time-of-flight distance sensors), there is no issue of accuracy.

For example, the GP2D12 sensors are uncalibrated distance sensors. Each individual one is almost guaranteed to output a different voltage at the same distance from an object. This is fine because the manufacturer never claims any consistent relationship between the output voltage and distance across samples.

Uncalibrated sensors must be calibrated before they can be used to measure any real physical quantity.