You might be interested in The Billion Prices Project, which calculates price changes by scraping online product prices. They make the data available.

http://www.thebillionpricesproject.com/

Spoiler: Billion Prices Project has mostly tracked CPI within 1-2%

The CPI is a weighted average of several categories. and some of those categories severely underestimate inflation. For instance, the CPI says new car prices haven't increased in the last 20 years but, that's obviously not true, if you calculate the real cpi for say a corrolla or a camaro or whatever model you choose, you can see it's gone up about 40 to 60% in that time which means for that category, they're undercounting CPI by almost 2 to 3 %.

I think they're trying to prevent people from calculating the real CPI. there's alot at stake: the bond market, social security, federal interest payments, perception of real wages, real productivity per capita number, etc.

The BLS makes nearly all of their products publicly available for free. You can poke around the old-school way here: https://download.bls.gov/pub/time.series/

They have an API with documentation here: https://www.bls.gov/developers/

And a few other options here: https://www.bls.gov/data/

But I suspect that what you mean is that the raw data used to calculate these metrics isn’t available. Such as the “worker X on 25 Feb found that the price of a pound of flour at the Kroger store #357 is $1.” I suspect there are two reasons. (I can’t say for sure because I don’t work at the BLS, but I am a statistician, work for the government, and have been involved in decisions not to release data).

1. The BLS almost certainly contracts the leg work for the CPI. While the calculations are relatively simple (arguments about methodology excluded), the work to collect prices nationwide is nontrivial. Including permission to release the data publicly likely increased the cost of the contract. These data vendors also sell their price data to other “businesses intelligence” companies, and allowing the public release hurts their other business prospects, so they would charge a premium for it. And ironic as it may seem, government agencies/workers are interested being good stewards of the public’s tax dollars and had to make a value decision to not buy the rights to release the data.

2. For anything that isn’t legally/contractually prohibited from release, there may have been a conscious decision that the data at its most granular level either wasn’t useful to the public at all, or was likely to be misleading/misused because of critical gaps in what can be released. If the vendor for Alabama prices allowed release but the vendor for California prices did not, they may have just made the decision that releasing incomplete data set wasn’t a good idea.

From the text:

> Multiple confidentiality issues arise in the production of the CPI. One set of issues arises out of the need to prevent unauthorized access of data that are embargoed, or yet to be released to the public. because the CPI data can affect financial markets, it is essential to ensure that no one without authorization has access to the data before release. BLS personnel who do see the data ahead of time are restricted by law from engaging in certain financial transactions during the period where they have seen data that are not public. Pre-release data are encrypted and always kept on secure servers, with any hard copies locked in secured areas.

Disclaimer: Sharing links to my own content

I hear you. I tried recreating the CPI for India and couldn't get the data needed. (see https://arun.tanksali.com/topic/rpi/). I eventually thought I can come with a Personal Price Index which reflects how inflation is when seen from my personal perspective. I took a basket of goods derived from our household consumption and scraped prices for a year (till last month). See (2) for data. Obviously, CPI represents the average citizen and no individual is likely to fit that definition well. I am no economics expert but I expected some correlation between the published CPI and my own observations but there were times they were moving in opposite directions. 1: https://arun.tanksali.com/topic/rpi/ 2: https://realpi.tanksali.com/#/app/dashboard

What exactly is it that you want, but can't obtain?

Beyond the plethora of data that is published, you could submit a FOIA request for anything you feel is in the possession of the BLS, but not being published.

Isn't this it?

https://catalog.data.gov/dataset/consumer-price-index-cpi

Because if you could lay your hands on the data and calculate the CPI for yourself, you would find that the 'official' CPI is pure baloney.

The CPI is a propaganda tool. It is designed to keep the real inflation hidden to make it seem that inflation is not a real thing to worry about. Because it is formulated in secret, they can manipulate it to give a fairly rosy picture. The published CPI never panics.