A coho study is -
An analytical study
A descriptive study
A corelational trail
An experimental study
Coho study is also known as incidence study. The cohos are identified prior to the appearance of disease under investigation. The study group so defined are observed over a period of time to determine the frequency of disease among them Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 83
Epidemiology