The simplest of all pre-experimental group research designs is the one-shot case study, also known as the cross-sectional study. The one-shot case study is appropriate for answering exploratory and descriptive research questions related to what exists at a certain point in time.

We just got out on the top and there was a little skift of snow a-fallin'.

This washing machine never sticks to the programmed cycle. It has a mind of its own.

Charlatans and quacksalvers treated the sick and dying and peddled medicines to keep one healthy but operated under no license to do so. […] Though often tarred as frauds, their methods often differed little from those of the professionals.