Time series modeling of daily abandoned calls in a call centre

Models for evaluating and predicting the short periodic time series in daily abandoned calls in a call center are developed. Abandonment of calls due to impatient is an identified problem among most call centers. The two competing models were derived using Fourier series and the Box and Jenkins modeling approaches. The selected models were shown to be both  parsimonious and adequate using the P-P plots, Q-Q plots and residual analysis. In validating and comparing the models some efficiency measures were used with a view to determining the model which best represent the population under investigation. Fourier series model was found to be more efficient than Box and Jenkins model. The data for application were got from a GSM telephone provider. KEY WORDS : Call center; Tele-queue; abandoned calls; Fourier time series; Periodogram; Moving average, Autoregressive process