Accuracy

Summary

Measures Recommendations' accuracy based on users' access to the services. A value of 1, indicates that the RS model got all the predictions right, and a value of 0 indicates that the RS model did not make a single correct prediction

Description

The accuracy $(A$ of the recommendations is based on users' access to the services. A value of 1, indicates that the RS model got all the predictions right, and a value of 0 indicates that the RS model did not make a single correct prediction. Generally, the Accuracy mathematical expression is defined as: $A=\frac{Number\;of\;correct\;predictions}{Total\;number\;of\;predictions}$

In RS Metrics the computation is determined by the following formula: $Accuracy=\frac{Number\;of\;correctly\;recommended\;services}{Total\;number\;of\;services}$where correctness is defined as if the service is both accessed by the user and also it is recommended by the RS

Output

Type	Float
Min	0
Max	1

info

A value of 1, indicates that the RS model got all the predictions right, and a value of 0 indicates that the RS model did not make a single correct prediction.

Prerequisites:

• recommendations without anonymous users
• all available users (with their accessed services)
• all available services

Process Flow:

• Clean up

Recommendations clean up; entries removal where users or services are not found in "users" or "services" accordingly

• Vector creation of the Accessed Services

For each user create a vector at the size of the number of the services, and assign a binary value for each service with a value of 1 if it is found in the user's accessed services, or 0 if it is not

• Vector creation of the Recommended Services

For each user create a vector at the size of the number of the services, and assign a binary value for each service with a value of 1 if it is recommended to the user, or 0 if it is not

• Accuracy score computation

For each user compute the average value of the difference vector; a vector which states True if service is found in both accessed and recommended vectors or False if it is not

• Mean value of Accuracy score

Computation of the overall value by calculating the mean value of each user's accuracy score