You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Which of the following is not true about non-randomized trials? and explain in detail?
Non-randomized trials ( i.e. Those depaing from strict randomization for practical purposes but in such a manner that non-randomization does not seriously affect the theoretical basis of conclusions ( refer pg 81, park 23 rd edition)