Why does species outside the quadrat doesn't matter?

A quadrat is a simple device for marking out a small area. For young children at primary school the quadrat is often a convenient way of focusing a pupil's attention on a particular small area. At secondary level, pupils should understand how quadrats can be used to sample a larger area. By recording information from a number of quadrats placed within a larger study area, they can obtain a representative sample of the whole area, which may be too big to describe in full.