ItemLift {exametrika}R Documentation

Item Lift

Description

The lift is a commonly used index in a POS data analysis. The item lift of Item k to Item j is defined as follow: l_{jk} = \frac{p_{k\mid j}}{p_k} This function is applicable only to binary response data.

Usage

ItemLift(U, na = NULL, Z = NULL, w = NULL, ...)

Arguments

U

U is a data matrix of the type matrix or data.frame.

na

na argument specifies the numbers or characters to be treated as missing values.

Z

Z is a missing indicator matrix of the type matrix or data.frame

w

w is item weight vector

...

Internal parameters for maintaining compatibility with the binary data processing system. Not intended for direct use.

Value

A matrix of item lift values with exametrika class. Each element (j,k) represents the lift value of item k given item j, which indicates how much more likely item k is to be correct given that item j was answered correctly.

Note

This function is implemented using a binary data compatibility wrapper and will raise an error if used with polytomous data.

References

Brin, S., Motwani, R., Ullman, J., & Tsur, S. (1997). Dynamic itemset counting and implication rules for market basket data. In Proceedings of ACM SIGMOD International Conference on Management of Data (pp. 255–264). https://dl.acm.org/doi/10.1145/253262.253325

Examples

# example code
# Calculate ItemLift using sample dataset J5S10
ItemLift(J5S10)

[Package exametrika version 1.1.0 Index]