Estimating the Bridging Day Effect on Turkish Industrial Production

[EN] Adjusting the economic data for seasonal and calendar effects is of crucial importance for understanding the underlying information for the time series under consideration. However, irregular factors such as bridging days may impede the analysts perform the most accurate seasonal adjustment and lead to wrong adjusted values. In this study we aim to identify the impact of bridging days on Industrial Production Index (IPI) in Turkey by also taking into account the time of the year the bridging days fall. The results show that while national holiday bridging days do not affect IPI, religious holiday bridging days do. However, the magnitude of impact changes according to the season of the year. The production loss impact during a religious holiday in the high season (June -October) is around 40 percent, it is reduced by half during the low season. [TR] Iktisadi faaliyete iliskin verilerin ana egilimlerini daha iyi anlamak icin ilgili zaman serisi verilerinin mevsim ve takvim etkilerinden arindirilmasi buyuk onem arz etmektedir. Ancak kopru gunu gibi duzensiz, analiz yapanlarin en dogru mevsimsellikten arindirmayi yapmalarina engel teskil edebilmekte ve yanlis arindirilmis sonuclar elde etmelerine yol acabilmektedir. Bu calismada kopru gunlerinin Sanayi Uretim Endeksi (SUE) uzerine etkilerinin, kopru gunlerinin hangi mevsime denk geldigi de dikkate alinarak hesaplanmasi amaclanmaktadir. Sonuclar milli bayramlara denk gelen kopru gunlerinin SUE’yi etkilemedigini, ancak dini bayramlara denk gelen kopru gunlerinin etkiledigini ortaya koymaktadir. Ancak bu etkinin buyuklugunun kopru gununun denk dustugu sezona gore degistigi tespit edilmistir. Uretim kaybi yaz turizmi sezonuna (Haziran – Ekim) denk gelen kopru gunlerinde normal bir calisma gunune gore yuzde 40 azalirken, bu azalis yilin kalan donemlerinde bu degerin yarisina inmektedir.