Persian metres The terminology for metrical system used in classical and classical-style Persian poetry is the same as that of Classical Arabic, even though these are quite different in both origin and structure.
Basic validation of qualitative tests Basic Method Validation Basic validation of qualitative tests In this first lesson, Dr. Paulo Pereira introduces some of the basic concepts of method validation that apply when a qualitative method is being evaluated.
Basic Validation of Qualitative Tests Paulo Pereira, PhD November Introduction The validation of qualitative tests differs from the quantitative tests principally since there are no numerical results but binary results, e. Immediately these tests are recognized in medical laboratories according to this designation.
However, they could be related to nominal quantities or ordinal quantities .
The validation concepts in this essay only deal with the final binary result that can be applied to any qualitative test. The cases in this lesson use virology results. However, the concepts can be applied to any other qualitative test.
Purpose Verification and validation definitions are sometimes confusing in practice. In contrast to the verification explanation, validation is directly related to the interested parties requirements, such as the accuracy of clinical decision required by the patients.
Erroneous binary results, i. Therefore, the qualitative test validation goal is to confirm, based on data, that the requirements for its use have been fulfilled. These specifications should be intended to assure a nonsignificant risk of false results.
Reverend Thomas Bayes developed a probabilistic model for defining the likelihood that an element would be a member of a specific class. On a qualitative test view, the element is the binary result, and the class is the disease or nondisease group of subjects.
So, the model determines the probability of a patient or a healthy individual to be truly classified as infected or noninfected. The comparison of methods can be determined primarily when the comparator is the diagnostic accuracy criteria, or it can be determined secondarily when the comparator is other than the diagnostic accuracy criteria.
The area under the receiver operating characteristic ROC curve is another diagnostic accuracy measurement, complementary to the sensitivity and specificity .
Sampling The patient samples for this validation should be taken from the target population. A representative sampling of infected individuals can be difficult to obtain for a virology qualitative test. The sources of uncertainty in chemistry tests are related principally to the pre  and the analytical phase, to the intra- and inter-individual variation, and to the effects of diseases , drugs  and herbs and natural products .
In a virology tests, however, several additional sources variation can affect the accuracy of the results, such as the types and sub-types of the agent, mutations , and the seronegative window period .
Note that the infected individual sampling must only have samples from diagnosed individuals. If the only available samples are from patient samples with a known result from another screening test, this uses the secondary model. Samples from noninfected individuals are much easier to obtain. Regular blood donors are an example of a suggested population.
In this sampling, the target population is the set of generic healthy individuals. The number of samples is a limitation to the statistical power of the study. As many samples should be used as is practical. The laboratorian should understand this limitation when defining the specifications.
The laboratorian can choose a shorter period. However, the reproducibility conditions of the study should be assured to reliable estimates. When the comparator is the diagnostic accuracy criteria. There is commercial statistical software available to support this study.
Nevertheless, the determination can easily be performed in a spreadsheet. Table 1 shows a 2x2 contingency table and the equations to determine the diagnostic sensitivity and specificity.
Complementary measurements can be performed, but their importance to the validation is minor. From the laboratorian's viewpoint, the sensitivity and specificity are the critical determinations. From the physician's perspective, the core measurements are the prediction values since they describe the probability of a result to accurately diagnose a subject.
The laboratorian should understand that this inference is limited by the characteristics of the samples. Consequently, if the sampling diagnostic accuracy is biased, the confidence interval is also.In quantitative risk assessment an annualized loss expectancy (ALE) may be used to justify the cost of implementing countermeasures to protect an asset.
This may be calculated by multiplying the single loss expectancy (SLE), which is the loss of value based on a single security incident, with the annualized rate of occurrence (ARO), which is an estimate of how often a threat would be.
Configurational Comparative Methods paves the way for an innovative approach to empirical scientific work through a strategy that integrates key strengths of both qualitative (case-oriented) and quantitative (variable-oriented) approaches.
This first-of-its-kind text is ideally suited for "small-N" or "intermediate-N" research situations, which both mainstream qualitative and quantitative. Tesco Labs India – Graduate Placement Program. Tesco Labs India recently launched a first-of-its kind initiative, conducting a six-week placement programme for the technology graduates who joined us from premier institutes across the country.
Keywords: qualitative research methods, features of qualitative research, features of quantitative research Most of us are researchers most of the time.
We dont necessarily think of ourselves as researchers but research is really about collecting information that tells us about something and it helps us make informed decisions. Abstract: This essay is a contribution to the question whether grounded theory methodology (in the variant of STRAUSS & CORBIN) contains an abductive research logic as developed in the work of Charles Sanders PEIRCE.
After going through the works of STRAUSS and CORBIN I answer the question with a. Related articles. Limitations and weakness of quantitative research methods Quantitative research main purpose is the quantification of the data. It allows generalisations of the results by measuring the views and responses of the sample population.