Provided are a leave of absence prediction system and the like capable of predicting whether an employees, etc. will take a leave of absence in a predetermined time. A leave of absence prediction system according to an aspect of the present invention is provided with: prediction rule learning means for generating a prediction rule regarding prediction of a likelihood of a leave of absence based on first attendance management information including a time-series factor concerning an employee and on information indicating presence or absence of the leave of absence concerning the employee relating to each piece of the first attendance management information, the likelihood of the leave of absence being a likelihood of the employee taking the leave of absence in a predetermined time; and prediction means for predicting the likelihood of the employee as a target of prediction taking the leave of absence based on second attendance management information including a time-series factor with respect to an employee as the target of prediction and on the prediction rule.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A leave of absence prediction system comprising: a processor; and a memory storing a program executed by the processor to realize units, including: a prediction rule learning unit configured to generate a prediction rule regarding prediction of a likelihood of a leave of absence based on first attendance management information including a time-series factor concerning an employee and on information indicating presence or absence of the leave of absence concerning the employee relating to each piece of the first attendance management information, the likelihood of the leave of absence being a likelihood of one employee taking the leave of absence in a predetermined time; and a prediction unit configured to predict the likelihood of the employee as a target of prediction taking the leave of absence based on second attendance management information including a time-series factor with respect to an employee as the target of prediction and on the prediction rule. 2. The leave of absence prediction system according to claim 1, wherein the first attendance management information concerning the employee having taken the leave of absence includes a time-series factor for a period prior to the predetermined time from a time point the employee taking the leave of absence. 3. The leave of absence prediction system according to claim 1, wherein the first attendance management information concerning the employee having not taken the leave of absence includes a time-series factor for a period prior to the predetermined time from a time point the employee working normally. 4. The leave of absence prediction system according to claim 3, wherein the first attendance management information concerning the employee having not taken the leave of absence includes a time-series factor for a period further prior to a predetermined period from the predetermined time prior to the time point the employee working normally. 5. The leave of absence prediction system according to claim 1, wherein the likelihood of the leave of absence represents a likelihood that a final attendance date of the employee is in the predetermined time. 6. The leave of absence prediction system according to claim 1, wherein the prediction rule learning unit classifies the first attendance management information into a plurality of clusters in accordance with a predetermined condition, and generates the prediction rules for the plurality of clusters respectively; and the prediction unit determines into which of the plurality of clusters the second attendance management information is classified, and predicts the likelihood of the leave of absence based on the prediction rule generated for the cluster determined. 7. The leave of absence prediction system according to claim 1, wherein the prediction unit derives a temporal variation in the predicted likelihood of the leave of absence. 8. The leave of absence prediction system according to claim 1, wherein the prediction unit predicts and derives degrees of the likelihoods of the plurality of employees as the target of prediction taking the leaves of absence. 9. The leave of absence prediction system according to claim 1, wherein the prediction unit derives a candidate for a factor causing the leave of absence when predicting that the employee as the target of prediction is likely to take the leave of absence. 10. The leave of absence prediction system according to claim 1, wherein the prediction rule learning unit generates the prediction rule regarding prediction of the likelihood of the employee taking leave of absence in a plurality of the predetermined times that are different from each other, and the prediction unit predicts a plurality of the likelihood of the employee as the target of prediction taking the leave of absence, each of the a plurality of the likelihood of the employee as the target of prediction taking the leave of absence respectively relating to the plurality of the predetermined times that are different from each other. 11. A prediction rule learning device comprising: a processor; and a memory storing a program executed by the processor to realize units, including: a prediction rule learning unit configured to generate a prediction rule regarding prediction of a likelihood of a leave of absence based on first attendance management information including a time-series factor concerning an employee and on information indicating presence or absence of a leave of absence concerning the employee relating to each piece of the first attendance management information, the likelihood of a leave of absence being a likelihood of one employee taking the leave of absence in a predetermined time. 12. A prediction device comprising: a processor; and a memory storing a program executed by the processor to realize units, including: a prediction unit configured to predict a likelihood of an employee as a target of prediction taking a leave of absence based on second attendance management information including a time-series factor with respect to the employee as the target of prediction and on a prediction rule concerning prediction of a likelihood of the leave of absence, the likelihood of the leave of absence being a likelihood of an employee taking the leave of absence in a predetermined time. 13. A leave of absence prediction method comprising: generating a prediction rule regarding prediction of a likelihood of a leave of absence based on first attendance management information including a time-series factor concerning an employee and on information indicating presence or absence of the leave of absence concerning the employee relating to each piece of the first attendance management information, the likelihood of the leave of absence being a likelihood of one employee taking the leave of absence in a predetermined time; and predicting the likelihood of the employee as a target of prediction taking the leave of absence based on second attendance management information including a time-series factor with respect to an employee as the target of prediction and on the prediction rule. 14. A computer-readable recording medium storing a program causing a computer to execute: processing of generating a prediction rule concerning prediction of a likelihood of a leave of absence based on first attendance management information including a time-series factor concerning an employee and on information indicating presence or absence of the leave of absence concerning the employee relating to each item of the first attendance management information, the likelihood of the leave of absence being a likelihood of one employee taking the leave of absence in a predetermined time; and processing of predicting the likelihood of the employee as a target of prediction taking the leave of absence based on second attendance management information including a time-series factor with respect to an employee as the target of prediction and on the prediction rule.