Provide a summary of the study background, aims, and design.
II. Background and Significance/Preliminary Studies
Describe the current environment that is the basis for the proposed research, including a presentation of the problem (with references) and a review of current literature. Include a critical evaluation of current knowledge and preliminary studies related to the proposed research and describe how this proposal will enhance this knowledge.
III. Study Aims
Describe the purpose of the study, including identification of specific primary objectives/hypotheses. Secondary objectives/hypotheses should be described as necessary.
IV. Administrative Organization
Describe the participating units, including other participating study sites, laboratories, data management center, and coordinating center as applicable.
V. Study Design
- Experimental design of the study (e.g., single-blind, double-blind)
- Study population general description
- Sample size determination and power analyses
- Study outcomes/endpoints
VI. Study Procedures
a. Subject selection procedures
i. Sampling plan including Inclusion/Exclusion criteria (subject and disease characteristics)
ii. Recruitment procedures
1) Where will recruitment occur?
2) Where and when will consent be obtained?
3) Who will obtain consent?
4) What is the advertising plan, if applicable?
5) What recruitment materials will be provided to the potential participant (brochures/information sheets/video presentation)?
iii. Screening procedures
1) What procedures are required for screening?
2) What is the screening schedule (number of visits, length of visits)?
3) Which screening tests/procedures are part of standard care and which are for research purposes only?
4) What happens with screen failures (including any data gathered during screening)?
b. Randomization procedures (if applicable)
c. Study Intervention
i. For Drug/device studies:
1) Active study agents
2) Placebo study agents
3) Blinding/labeling/preparation of agents
6) Toxicities and guidelines for adjustments
ii. For Other types of intervention studies:
1) Active intervention description
2) Control group, if applicable
d. Study Assessments and Activities
1) Describe all study procedures, assessments, and subject activities
2) Provide a schedule of all study assessments and subject activities, including a tabular representation or timeline as applicable
VII. Safety Monitoring Plan
a. Definition of adverse events, serious adverse events
b. What procedures will be used to monitor subject safety?
c. Who (list names) will identify, document, and report adverse events?
d. What is the frequency for review of summarized safety information and who will perform the review (e.g., safety monitoring board)?
e. What are the stopping rules with regard to efficacy and safety?
VIII. Analysis Plan
Describe statistical analysis methods as appropriate. For example, will intention-to-treat methodology be used in the analysis? Will there be any sample stratification?
IX. Literature Cited
VARIABILITY AND ITS MEASURES
Variability is very much found in Medicine or biology rather than in physics or chemistry. Biological data, quantitative or qualitative collected by measurement or counting are very variable. Variability is essentially a normal character or occurrence of variability is a biological phenomenon. For e.g.:- The cure rate in any disease such as typhoid with the same drug varies in different patients, birth rates of two towns are seldom equal.
I Biological variability
Biological variability is the variability that occurs within certain accepted biological limits. Variability exhibited by the individuals in similar environments when compared as regards to sex, class and other attributes but the difference noted may be small and is said to occur by chance is called biological variability. It may be the normal or natural difference in all individuals or groups within certain acceptable limits. The limits of variability of a variable character from the mean and proportion of a population can be studied by the application of certain principles of variation such as normal distribution, range etc and the extend of variability of a variable character from the mean and proportion of a population can be studied by certain measures of dispersion such as range, quartile deviation, standard deviation and standard error.
1. Individual variability
e.g.; – The heights and weights of two individuals vary. To find whether the heights of two students differing in units are normal or not we find the mean and standard deviation of heights of the population by taking a large sample(n>30).
2. Periodical variability
e.g.;- The same individuals show variation in temperature, pulse rate, blood pressure WBC count etc. at different times of the day, in illness, during rest, after exercise or after meals. The variations can be studied or analysed by applying suitable statistical techniques.
3. Class, group or category variability
e.g.;- Height, weight , blood pressure etc. vary from class to class depending on age, sex, social status or nature of work. Mean height of males vary from mean height of females.
4. Sampling variability
The values of any sample will differ from those of the population and further there will be variability from one sample to another sample. This is a biological variability of samples and is called sampling variability or sampling error or statistical error. Sampling error is a chance variability which can be reduced by increasing the sample size but cannot be totally eliminated.
II Real variability
Real variability is the variability occurring when the difference between two readings, observations or values of classes or samples is more than the defined limits in universe for which the variability occurring may not be natural or inherent in the samples but lies in external factors. E.g.;- Statistically cure rate for a disease may be due to a drug and not by chance. Higher rate of coronary disease in bus drivers than that in conductors may not be a biological chance but may be due to strain or tension involved in the nature of the job. If the variability is found to be real, the offending external factor has to be found and duly dealt with.
III Experimental variability
Error or difference or variation due to materials, methods , procedures employed in the study or defects in the techniques involved in the experiment.
1. Observer error observer error may be subjective or objective.
An interviewer may alter some information thereby adding a number of errors while noting human particulars unless trained properly. He may even ask embarrassing questions which the person may not like to answer, some subjects are very keen while others do not wish to give any information or on certain occasions, the situation may not be favourable to seek information.
Objective errors may be added by an untrained observer while recording the measurements such as blood pressure, pulse rate etc. The parallax error due to different positions of the observer while reading the fluid level in a thermometer or a glass tube or in recording height, weight etc. Biochemical tests may give different results in different hands and so on.
2. Instrumental error
The error produced due to the defects in the instruments which cause undesirable variability or the error in observations leading to wrong conclusions and colossal waste of money , time and labour is termed as instrumental error. This may be negligible or gross. Observer and Instrumental errors are sometimes called non- sampling errors.
3. Sampling Errors
The errors occurring in the process of the selection of the sample is termed as sampling errors. A sample drawn should not be biased or too small to draw conclusions. It should be representative and of sufficiently large size to stand statistical tests. In the medical field and in the field of epidemiological studies on e has to be careful about sampling bias or defects. Hospital based studies are mostly biased because the sample of the patients because the sample of study is drawn from nearby strata of society. Moreover many come to hospital at a late stage.
Experimental variability is not unusual but a common occurrence about which one must be careful in any scientific study so that the bias may be minimised.
Measures of Variability
Measures of variability (or measure of dispersion ) of observations help to find how individual observations are dispersed or scattered around the mean of the large series. The various measures of dispersion in common use are
- Quartile deviation
- Mean deviation
- Standard deviation.
- Coefficient of variation
Measures of variability of samples
- Standard error of mean
- Standard error of difference between means
- Standard error of proportion
- Standard error of difference between means
- Standard error of correlation coefficient
- Standard deviation of regression coefficient.