Construction and Seasonal Patterns of Islamic Hijri Calendar Monthly Time Series: An Application to Consumer Price Index (CPI) in Pakistan

Time series data are compiled and analysed in accordance with Gregorian calendar, given its world-wise use. This paper presents a simple method of constructing time series in accordance with Hijri Calendar from an already compiled Gregorian time series. Preliminary seasonal analysis of Hijri time series for CPI in Pakistan provides new insights of price behavior that depends both on Gregorian and Hijri seasonality. A spliced series of monthly CPI from January 1976 to December 2008 spanning 33 Gregorian years (396 Gregorian months) is used to capture a full cycle of 34 Hijri years (408 Hijri months). Method presented is general and can be used to construct and analyse any variable of interest. [SBP WP No. 50]. URL:[http://www.sbp.org.pk/publications/wpapers/2012/wp50.pdf].