What characteristic is essential for systematic random sampling?

The essential characteristic of systematic random sampling is interval-based selection. This method involves selecting samples from a larger population at regular intervals. For instance, if a researcher decides to sample every 10th individual in a list, the starting point is randomly chosen, and every 10th individual is included in the sample thereafter. This approach ensures that the sample is spread evenly across the population.

In systematic random sampling, the interval between selections helps maintain a structured sampling procedure, making it easier to implement compared to other sampling methods. This characteristic enhances the representativeness of the sample while still incorporating an element of randomness through the initial selection process. Because of this systematic approach, researchers can also efficiently collect data without having to rely solely on wholly random selections, which can sometimes introduce skewed samples. Therefore, interval-based selection is critical for achieving a balanced and effective sampling strategy.