The term for a quasi-experimental design with at least one treatment group and one comparison group, in which the participants are measured once and have not been randomly assigned to the groups is ''non equivalent control group design''
Step-by-step explanation:
A quasi-experiment is a research or experiment method that does not make use of random assignments. Quasi experiments are used to study the impact of an intervention or an experiment on a control group. The treatment conditions can be controlled in non equivalent control group design.
But the control is not based on random assignment and instead some other criterion is used to assign to the groups. With such experiments it is not always possible to find out the actual impact of the experiment on the groups chosen because of lack of randomization.