What is discriminatory power of a model?

What is discriminatory power of a model?

The discriminatory power of a classification or typing Model is the likelihood that the Model will assign a different type to two unrelated outcomes randomly sampled from the population under consideration. This measure of Model performance is applicable to statistical Models with cardinal or ordinal output.

What is the formula of discriminating power?

The Discrimination Index (D) is computed from equal-sized high and low scoring groups on the test. Subtract the number of successes by the low group on the item from the number of successes by the high group, and divide this difference by the size of a group. The range of this index is +1 to -1.

What is the power of item discrimination?

Item discrimination refers to the ability of an item to differentiate among students on the basis of how well they know the material being tested. Various hand calculation procedures have traditionally been used to compare item responses to total test scores using high and low scoring groups of students.

How do you find the discriminatory power of a model?

Statistical Measures of Discriminatory Power

1. Cumulative Accuracy Profile (CAP) and its summary index, the Accuracy Ratio (AR),
2. Receiver Operating Characteristic (ROC) and its summary indices, the ROC measure and the Pietra coefficient,
3. Bayesian Error Rate,

What does a negative discrimination index mean?

A negative discrimination index may indicate that the item is measuring something other than what the rest of the test is measuring. More often, it is a sign that the item has been mis-keyed. In other words, if an item is either very easy or very hard, it is not likely to be very discriminating.

What is discrimination level?

The discrimination index of an item is the ability to distinguish high and low scoring learners. The closer this value is to 1, the better the item distinguishes the learners who get a high score from those who get a low score.

How do you identify item discrimination?

Determine the Discrimination Index by subtracting the number of students in the lower group who got the item correct from the number of students in the upper group who got the item correct. Then, divide by the number of students in each group (in this case, there are five in each group).

What ROC curve means?

receiver operating characteristic curve
An ROC curve (receiver operating characteristic curve) is a graph showing the performance of a classification model at all classification thresholds.

What is a good accuracy ratio?

For a successful model, this value should lie between 50% and 100% of the maximum, with a higher percentage for stronger models. In sporadic cases, the accuracy ratio can be negative.

How do you calculate discrimination?

How do you interpret discrimination?

The interpretation of High-Low Discrimination is similar to the interpretation of correlational indices: positive values indicate good discrimination, values near zero indicate that there is little discrimination, and negative discrimination indicates that the item is easier for low-scoring participants.

Which is the best definition of discriminating power?

Psychology Definition of DISCRIMINATING POWER: Able to measure and distinguish between 2 groups being measured.

How is the power of discrimination used in paternity analysis?

A measure of discrimination often used in paternity analyses is the paternity index (PI), a means for presenting the genetic odds in favor of paternity given the genotypes for the mother, child and alleged father. An alternative calculation used in paternity analyses is the power of exclusion.

How to calculate the discriminating power for K attributes?

The computer system, which calculates the Discriminating Power for k attributes in combination, is termed a computer search of “order k”. If one of the attributes provides discrete data then Ej could be set at zero.