The Consumer Price Index for All Urban Consumers (Inflation Rate)

Transcription

1 The Cosumer Prce Idex for All Urba Cosumers (Iflato Rate) Itroducto: The Cosumer Prce Idex (CPI) s the measure of the average prce chage of goods ad servces cosumed by Iraa households. Ths measure, as a tool for measurg geeral prce level of goods ad servces cosumed by households, s oe of the best crtera for measurg chages purchasg power of moey sde the coutry. Ths dex s used to adjust the wage ad salary blateral cotracts (escalatg cotracts) ad legal clams ad t s also the most mportat measure of the flato rate Ira. To get more famlar wth the Cosumer Prce Idex (CPI), the geographcal ad populato coverage of t, ad the cotets of the CPI basket, the methods of collectg formato ad the approach of calculatg the dex wll be dscussed brefly. I order to vestgate the varato of ths dex durg these years, the CPI dces for the years 1315 to 1395 are tabulated at the last page. 1. Geographcal Coverage Wder geographcal coverage of the dex cosderably creases the degree of ts accuracy ad valdty. It's obvous that cosumpto culture ad atttudes ca partly be the result of clmatc ad geographcal characterstcs of each rego. To atta a approprate geographcal coverage, we have scetfcally selected 79 sample ctes dfferet provces of the coutry. These samples ca reflect prce chages for all urba areas ad for each provce as well. To calculate the total dex for urba areas Ira, we apply a statstcal method to combe the 31 depedetly produced dces each provce. 2. Populato Coverage of CPI I 1395 (Base Year 1395=1), after selectg sample ctes, we have scetfcally selected almost 176 households from resdet households 79 1

2 ctes. The average expedture of these households s the represetatve of the average expedture for the whole coutry. These samples have bee selected from every type of households wth dfferet comes ad dfferet cosumpto patters. Data collectors vst the selected households to obta the detaled formato o the purchased tems ad ther costs. The results are geeralzed to the total resdet households each provce ad the to the total urba areas the coutry. 3. Goods ad Servces of CPI Basket Accordg to the results of the Household Budget Survey, goods ad servces are selected for the CPI basket due to ther relatve mportace (weght) the household total expedture. These weghts are updated perodcally, sce the cosumer purchasg patters chage durg the years. I 1395, the cotets of the CPI basket were updated (revsed) usg the outcomes of the HBS of the curret year, ad 386 tems of goods ad servces (cludg 294 tems of goods ad 92 tems of servces) were selected scetfcally due to ther proporto of the total expedture of the household. Classfcato of goods ad servces Based o COICOP 1 classfcato, 386 tems of goods ad servces are dvded to 12 ma groups, whch ther weghtg coeffcets are as followed: 1 Classfcato of dvdual cosumpto by purpose 2

3 Base Descrpto year weght 1-Food ad Beverages 2-Tobacco 3-Clothg ad Footwear 4-Housg, Water, Electrcty, Gas ad other Fuels 5-Furshgs, Household Equpmet ad Route- Household Mateace 6-Health 7-Trasport 8-Commucato 9-Recreato ad Culture 1-Educato 11-Restaurats ad Hotels 12-Mscellaeous Goods ad Servces Each of the ma groups has bee dvded to some subgroups ad each subgroup cludes several tems of goods ad servces wth smlar characterstcs accordg to COICOP classfcato. The CPI basket comprses of 14 tems of food ad beverages group ad 282 tems of o-food goods ad servces. 4. Methods of collectg data Data collectors of Geeral Drectorate of Ecoomc Statstcs of the cetral bak (who are professoal traed fxed questoers) vst thousads of 3

4 retal stores, servce establshmets, retal uts ad doctor's offces all over the coutry to obta formato o the prces of the thousads of tems used to track ad measure prce chages the CPI. I order to acheve real prces, data collectors vst 4 outlets every moth ad ask curret prces of more tha 121 quotatos of goods ad servces, ad vestgate ad regster the causes of prce fluctuato comparso wth the prevous moth prce. It s always tred to gather ad report the purchasg prce of each tem. 5. Method of calculatg the dex After collectg prces, the cosumer prce dex s calculated usg Laspeyres formula. Frst, the dex for each provce ad the for the whole coutry (overall CPI) s calculated. The formula s as below: I t, = PQ t 1 1 PQ 1 P 1 t1 Q PQ 1 Pt P t1 1 Where: I t, : The dex perod "t" relatve to the base perod. : The total umber of goods ad servces comprsg the CPI basket P t : The prce for tem "" at the perod "t" (observato perod) P : The prce for tem "" at the base perod Q : The quatty for tem "" at the base perod I ths method, oe year s usually selected as the base year. O the bass of the results of the household budget survey for the base year, the weght for ay tem (whch s the tem proporto of the total expedture) s calculated. So the weght of tem determes the cotrbuto of tem calculatg the CPI. I 4

5 order to compute the dex, prce chages of goods ad servces across the two perods ad t are measured as follows: The quattes of the base perod ad the prces of perod "t" are multpled to get sum of expedtures of total tems for perod "t". The total expedture for the base perod s calculated the same way. We get the overall dex by dvdg these two total expedtures ad the multplyg the result by Varato of the CPI durg Dfferet Years The chages of the CPI dces from 1315 to 1395 are tabulated below: 5

6 Year Idex Cetral Bak of the Islamc Republc of Ira The Cosumer Prce Idex for All Urba Cosumers Idex Numbers ad Ther Percet Chages Iflato Rate Year (1395=1) Idex Iflato Rate Year Idex Iflato Rate umber (percet) umber (percet) umber (percet)