1. Giữ sự can thiệp đơn giản. Tôi hiện đang phục vụ như là một thống kê trên một tập hợp các thử nghiệm trong đó, qua các cuộc biểu tình to nhất của tôi, mỗi bệnh nhân sẽ nhận được tiêm trong ba ngày, tự quản trị một loại thuốc trong sáu tháng, và tham dự đầu tiên semiweekly và sau đó là các buổi tư vấn hàng tuần trong cùng thời thời gian | Time period-to-time period variation Fraud sometimes laziness sometimes a misguided desire to please Improperly entered data Improperly stored data Among the more obvious preventive measures are the following 1. Keep the intervention simple. I am currently serving as a statistician on a set of trials in which over my loudest protests each patient will receive injections for three days self-administer a drug for six months and attend first semiweekly and then weekly counseling sessions over the same period. How likely are these patients to comply 2. Keep the experimental design simple crossover trials and fractional factorials are strictly for use in Phases I and II see Chapter 6 . 3. Keep the data collected to a minimum. 4. Pretest all questionnaires to detect ambiguities. 5. Use computer-assisted data entry to catch and correct data entry errors as they are committed see Chapter 10 . 6. Ensure the integrity and security of the stored data see Chapter 11 . 7. Prepare highly detailed procedures manuals for the investigators and investigational laboratories to ensure uniformity in treatment and in measurement. Provide a training program for the investigators with the same end in mind. The manual should include precise written instructions for measuring each primary and secondary end point. It should also specify how the data are to be collected. For example are data on current symptoms to be recorded by a member of the investigator s staff or selfadministered by the patient 8. Monitor the data and the data collection process. Perform frequent on-site audits. In one series of exceptionally poorly done studies Weiss et al. 2000 uncovered the following flaws Disparity between the reviewed records and the data presented at two international meetings No signed informed consent No record of approval for the investigational therapy Control regimen not as described in the protocol 9. Inspect the site where the drugs or devices are packaged specify the allowable tolerances .
