# The design effect

The design effect (deff) quantifies the extent to which the expected sampling error in a survey departs from the sampling error that can be expected under simple random sampling .

My question is

• Why do we compare expected sampling design with simple random sampling instead of other sampling method such as , systematic sampling , stratified sampling ?

\begin{align*} \mathbb{V}(\hat{Y}_{HT, SRS}) &= (1-\dfrac{n}{N}) \dfrac{S^2}{n} \\ \text{with : } S^2 &= \dfrac{1}{N-1} \sum_{k \in pop} (y_k - \bar{Y})^2 \end{align*}