How to Read an Economic Calendar · Lesson 2 of 6
The reference period, the release date and the prior print
One concept: reference period versus release date
Personal Consumption Expenditures Price Index: This series is moving to its original source (U.S. Bureau of Economic Analysis); it returns when it is read from there.
Why it matters
The newest CPI release on Kitalpha’s calendar was published on 2026-10-14, and its reference period reads September 2026. The two do not match, and they are not meant to. Behind the row, the CPI index record holds the index itself, whose latest level is 336.3 as of 2026-09-01. A reader who takes the publication date as the month measured, and the printed level as the headline, misreads both halves of the release. Which date is which, and which number is the one people quote, is the question here.
The concept
Every economic release is dated twice. The reference period is the span the agency measured: for consumer prices, a calendar month. The release date is the day the agency published the result, and it comes after the reference period ends because compiling takes time. The Bureau of Labor Statistics collects prices across a month and publishes the index in the second or third week of the following month; a release dated September describes August. The calendar row carries both dates and names the agency, and a reader who keeps them apart never has to ask which month a headline is about.
The figure the release reports is a level: a price index, the cost of a fixed basket of goods and services relative to a base period set to 100. The level on its own is rarely quoted, because its meaning depends on the base period. What is quoted is a change. The month-on-month rate divides the latest level by the prior print’s level, subtracts one and multiplies by 100. The year-on-year rate does the same with the level twelve months earlier, and it is the number headlines usually call inflation. Both are computed from the index record’s history, and both are different numbers from the level.
The prior print is the third piece. Each row names the release before it, with its own reference period and publication date, and the index record holds the series month by month, so the change from the prior print is a comparison of two levels in one record. The prior print is not a correction of anything; it is the previous month. Revisions, when an agency updates an earlier month’s figure, arrive inside a later release and are the subject of another lesson.
What the row does not carry is an expectation. On most calendars a surprise is the printed value minus a survey median, and a large surprise is what moves attention. Kitalpha licenses no survey and publishes no forecast, and its rows say so. That has a consequence for reading: on this site, the size of a print can be judged only against the series’ own earlier changes, and whether it surprised anyone cannot be judged at all. A large month-on-month change in a volatile series may be entirely usual; a small one in a steady series may be unusual. Size and surprise are different questions, and only the first has an answer here.
The timeline below sets the newest CPI release’s two dates beside its prior release. Look for the gap between the period measured and the day published, and notice that the printed levels sit on a different page from the row.
| Event | Date / state |
|---|---|
| Period measured | September 2026 |
| Published | 2026-10-14 at 08:30 EDT, by BLS |
| Prior release | Consumer Price Index, August 2026, published 2026-09-11 for August 2026 |
| Where the prints live | The index record: the latest level, the prior level and the full history |
Worked example
Take the newest CPI row and the index behind it as of 2026-09-01. The steps below read the latest level and the prior print’s level, compute the month-on-month change, then read the level twelve months earlier and compute the year-on-year change. Every figure comes from the indicator record on the date shown.
Record: Consumer Price Index, September 2026 · as of · U.S. Bureau of Labor Statistics
- Index level in the latest print, from the CPI indicator record 336.298 A price index: the cost of a fixed basket relative to a base period set to 100.
- Index level in the prior print 334.131
- Change from the prior print, in percent (month on month) 0.65%
- Index level twelve months earlier 324.245
- Change from a year earlier, in percent (year on year) 3.7% The twelve-month rate is the figure headlines usually call inflation.
Read the two rates against each other. The third line is the change from the prior print, the month’s own movement in prices; the fifth is the change over twelve months, the figure a headline calls inflation. The gap between the two is not a third rate: it is the distance between two comparisons, one against last month and one against the same month a year earlier, and it widens or narrows as the months that fell out of the twelve-month window are replaced by new ones. Both come from levels that were each measured in a single reference month and published the following month. Neither line says whether the print was expected; the row carries nothing to compare it with, and the only comparison the site offers is the series’ own history in the index record.
Faded example
Now the second gauge: the PCE price index, published by the Bureau of Economic Analysis, as of —. Its latest and prior levels are given. Complete the last step: the month-on-month change in percent.
This series is moving to its original source (U.S. Bureau of Economic Analysis); it returns when it is read from there. Open the record page
- PCE price index in the latest print, from the PCE indicator record—
- PCE price index in the prior print—
- % Tolerance ±0.01 %
Reveal the answer and the explanation
— — Divide the latest level by the prior level, subtract one and multiply by 100. The result is the month-on-month change in the PCE price index, the Bureau of Economic Analysis's gauge, computed exactly as the CPI's was; the two indexes cover different baskets and each record is read on its own latest month, so the two rates are two different numbers.
Stored on this device only; not graded.
Retrieval check
Mark your confidence before each answer. Every option carries an explanation; read the ones you rejected too.
-
1. The newest CPI row shows a reference period and a publication date in different months. The prices the release reports were measured in:
Choose your confidence first. -
2. Using the CPI indicator record, compute both rates the worked example computed and subtract the monthly rate from the twelve-month rate. Enter the gap in percentage points to one decimal, negative if the monthly rate is the larger.
Source record: Consumer Price Index (CPI-U), seasonally adjusted — BLS (as of 2026-09-01)
Tolerance ±0.1 ppChoose your confidence first. -
3. The CPI indicator record holds a level of the index for the latest print and one for the prior print. The level on its own is rarely the figure quoted, because:
Choose your confidence first. -
4. The newest CPI print shows a month-on-month change that a reader calls large. On Kitalpha, whether that print was a surprise:
Choose your confidence first.