Methodology

Every number on CheckedHome is a restatement of an official government record. We publish numbers and records, never ratings.

One source of record

Our electricity data comes from the U.S. Energy Information Administration, Annual Electric Power Industry Report (Form EIA-861). Utilities file it with the U.S. Energy Information Administration each year. We use the most recent final release (2024), plus the annual reliability files back to 2013 for history. We never use the unvalidated early release.

Imported, not retyped

A pipeline downloads EIA's published workbooks, pins each file by SHA-256 checksum, and normalizes the cells into the tables you see. Where EIA writes a blank for a metric a utility did not report, we render “Not reported to EIA,” never a zero. A missing outage number is an absence of a report, not an absence of outages.

Verified before it publishes

Before any batch goes live, a random sample of utilities is re-read cell by cell against EIA's own workbook, using a different tool than the import, and the outage arithmetic (CAIDI = SAIDI ÷ SAIFI) is confirmed on every sampled row. If the sample does not clear a 24-of-25 bar, nothing publishes.

What we compute, and what is EIA's

Outage figures (SAIDI, SAIFI) are the utilities' own filings. Average monthly bills and price per kilowatt-hour are computed by CheckedHome from EIA's residential revenue and sales, and state averages are our customer-weighted arithmetic on EIA's per-utility numbers. Wherever a figure is ours rather than EIA's, we say so on the page.

What the outage metrics mean

These are the official definitions from EIA's Form 861 instructions, quoted verbatim. We describe them rather than write our own.

SAIDI: minutes without power per year

SAIDI is the total number of minutes the average customer of a utility goes without power over a year, added up across every sustained outage.

The system average interruption duration index, or SAIDI, indicates the total duration of interruption for the average customer over a predefined period of time.

SAIDI = [Sum of customer minutes interrupted over the year] / [Total number of customers served]

SAIFI: how often power goes out per year

SAIFI is how many sustained interruptions the average customer experiences in a year. A sustained interruption is one lasting more than five minutes; brief flickers are not counted.

The system average interruption frequency index, or SAIFI, indicates how often the average customer experiences a sustained interruption (of over 5 minutes) over a predefined period of time.

SAIFI = [Sum of total number of customers interrupted over the year] / [Total number of customers served]

CAIDI: average length of one outage

CAIDI is the average duration of a single interruption, SAIDI divided by SAIFI. EIA publishes a CAIDI column in its workbook but does not define the term in the Form 861 instructions; it is the standard IEEE 1366 identity. We render EIA's published CAIDI value as EIA's own number, and confirm the SAIDI divided by SAIFI arithmetic on every spot-checked row.

Major Event Days: major storm days

A Major Event Day is a day with unusually severe outages, almost always a big storm, that a utility may separate from its everyday reliability numbers. This is why outage figures on this site are shown both with and without major storm days. EIA does not write its own definition; it points utilities to the IEEE 1366 standard:

If your entity calculates system average interruption duration index (SAIDI) and system average interruption frequency index (SAIFI) and determines Major Event Days in accordance with the IEEE 1366-2003 or IEEE 1366-2012 standard, answer ‘yes’ to questions 1 and 2 and complete Part B. If your entity calculates SAIDI and SAIFI via another method answer ‘yes’ to question 1 and no to question 2 then skip Part B and complete Part C.

The IEEE 1366 method sets a statistical threshold from each utility's own history, so a “major event” for a storm-prone utility is a bigger day than for a calm one. The full IEEE definition is a copyrighted standard, so we describe it here rather than quote it.

What we do not do

We do not rank utilities, assign scores or letter grades, or call any utility good or bad. A count and a computed average are facts; a grade is an editorial act, and we refuse it.