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)
## Default S3 method:
ItemLift(U, na = NULL, Z = NULL, w = NULL)
## S3 method for class 'binary'
ItemLift(U, na = NULL, Z = NULL, w = NULL)
Arguments
U |
Either an object of class "exametrika" or raw data. When raw data is given,
it is converted to the exametrika class with the |
na |
Values to be treated as missing values. |
Z |
Missing indicator matrix of type matrix or data.frame. Values of 1 indicate observed responses, while 0 indicates missing data. |
w |
Item weight vector specifying the relative importance of each item. |
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)