The data source is provided by the Directorate- General of Budget, Accounting and Statistics, Executive Yuan, R.O.C. of each county and city. The price checking area includes the 9 main representative counties and cities including New Taipei City, Taipei City, Taichung City, Tainan City, Kaohsiung City, Taoyuan City, Hsinchu City, Keelung City, Chiayi City. Following with the 8 counties including Yilan County, Miaoli County, Nantou County, Yunlin County, Pingtung County, Taitung County, Hualien County, Penghu County. Towns are the area for the main price check; counties and cities for rent checks only are the Hsinchu County, Changhua County and Chiayi County.
The date of the price check depends on the nature of the product. The municipalities (New Taipei City, Taipei City, Taichung City and Kaohsiung City) that have to publish their own consumer price index check 5 times a month (2 checks each in the first and last ten days, and 1 check on the 5th) , the remaining counties and cities will have the price checked 3 times a month (the 5th, 15th and 25th) or 9 times (the 2nd, 12th, 22nd, 5th, 15th, 25th, 8th, 18th and 28th), and 8 counties including Yilan County check price once a month (the15th) or 3 times (the 5th, 15th and 25th)
The price information obtained is calculated using the Laspeyres index. The index calculation method is to first weight the price ratio of each area for the price search with the area weight to obtain the item price ratio, and then use the full number of items to obtain the index.