Similar to simple random sampling, but instead of selecting random numbers from tables, you move through list (sample frame) picking every nth name.

You must first work out SAMPLING FRACTION by dividing population size by required sample size. E.g. for a population of 500 and a sample of 100, the sampling fraction is 1/5 i.e. you will select one person out of every five in the population. Random number needs to be used only to decide on starting point. With the sampling fraction of 1/5, the starting point must be within the first 5 people in your list

Disadvantage: Effect of periodicity (bias caused by particular characteristics arising in the sampling frame at regular units). An example of this would occur if you used a sampling frame of adult residents in an area composed of predominantly couples or young families. If this list was arranged: Husband / Wife / Husband / Wife etc. and if every tenth person was to be interviewed, there would be an increased chance of males being selected.