A quasi-[[experiment]] is an empirical [[interventional study]] used to estimate the causal impact of an [[intervention]] on target population without [[random]] assignment. Quasi-experimental [[research]] shares similarities with the traditional experimental design or [[randomized controlled trial]], but it specifically lacks the element of random [[assignment]] to treatment or control. Instead, quasi-experimental designs typically allow the researcher to control the assignment to the treatment condition, but using some criterion other than random assignment (e.g., an eligibility cutoff mark).