CPI tracks the cost of a fixed bundle of goods, intended to represent the purchases of a 'typical' person. However some things are excluded - mortgage, maybe rent, and some goods with volatile pricing.
If your purchases aren't typical, your expenses won't track the CPI. If your expenses other than CPI goods change, your total cost of living can change ...
For the CPI, there is actually federal employees whose job it is to visit various stores to collect the prices of specific items (boy's size-14 collared shirt made of 97 percent cotton). Planet Money did a great podcast on this, actually following one of these people for a day.
To understand this chart you need to see the underlying numbers from the Consumer Price Index The number for January 2014 is:
((CPI Jan14) - (CPI Jan13)) / (CPI Jan14)
That's supposed to reflect the inflation in the twelve months prior to Jan14. The same calculation is done in each month. The annual column represents the same calculation but substituting ...
FRED could do it. They've got the exchange rates, they've got the inflation rates as time series. They've also got various tools to link it to applications or databases. They won't, however, answer your exact question directly, a little bit of coding (and thought) is needed.
Here's why it's not uniformly possible to answer such questions: Even given only ...
The comparison is of the CPI of January 2014 to Jan 2015, this gives you the inflation for Jan 2015 ... Like wise for other months.
For example CPI in Jan 2013 was 97.1 and 99 in Jan 2014. Hence inflation in Jan 2014 is 2%
The explanation is in below para from same page
Inflation Rate data for the UK is available from 1988 onward. Year over Year ...
All of the above. There are scientific methods for surveying. Generally the "people with clipboards" is the most reliable, but is also the most expensive, so some might be getting the data directly from the retailers with some sampling for verification. The "margin of error" percentage is directly related to the method chosen.
The actual increase in the cost of living for one month over the previous month cannot be calculated from the annualized increase in cost over the entire previous year.
Consider the hypothetical case of a very stable economy, where prices stay constant for decades. Nevertheless, the authorities issue monthly statements, reporting that the change in the ...
In the style of the Bank of England's Inflation Calculator, you can do the calculation like so.
The third column is an index made from the inflation figures and the forth column shows the inflation-adjusted values.
Using the index to calculate the difference in costs, for example:
Cost in April = Cost in December x ( April price index / December price ...
CPI is an Index.
If an index started with 100 on Jan 1, and the "bimonthly cpi growth rate" is 1.32%, the index becomes 101.32 on Feb 28.
If an index is 101.32 on Feb 28, and the subsequent "bimonthly cpi growth rate" is 1.75%, the index becomes 101.32 x (1 + 0.0175) = 103.0931 on April 30.
Fast forward, the CPI growth aka Inflation over the year is ...
That is the correct way
You could, if you wanted, calculate it over any period of time, you just need to label it appropriately. Typically, people care about the annualized inflation number so that it can be compared to ones investment returns. E.g. My investments grew 10% this year, but inflation was 3%, so my investments only effectively grew by 7%.
Assume you're asking about things like the Consumer Price Index? Different countries have different approaches. If they're honest, then the statistical sampling is conducted independently and consistently, with a clear publication schedule, and - as littleadv answered - by the men with clipboards.
It is that publication schedule which leads to a little ...