Methodology and Sources

Certification profiles: vendor-page verification

Every certification's exam cost, exam format, and renewal terms are taken from that vendor's own current pricing and certification pages, verified directly against the vendor's published list price. Where a vendor's store cannot be read at verification time, such as a checkout flow behind a bot wall, we verify against that vendor's authorized-partner listings instead, rather than an unofficial reseller or a secondary source. Each certification profile carries its own last_verified date: the day someone actually re-checked the page against the vendor's current site, not the day the profile was first published.

Occupation pay: BLS OEWS joined by SOC code

Occupation pay figures come from the U.S. Bureau of Labor Statistics Occupational Employment and Wage Statistics (OEWS) national estimates, May 2025 vintage. Every certification is mapped to the single BLS Standard Occupational Classification (SOC) code it most directly serves, and that code is used to join the certification to its BLS median wage and employment figures at build time. Every occupation record links to its data.bls.gov/oesprofile source page, so any wage figure on the site can be checked against the original BLS table in one click. If a certification's SOC code has no matching record in our BLS dataset, the build fails outright rather than shipping a page with a missing or guessed number.

The no-premium rule

This is the spine of every number this site publishes about pay:

We do not publish a "salary lift" figure for holding a certification: no dataset isolates a causal wage premium for a credential, so any such number would be invented, not measured.

Occupation pay figures describe the occupation a certification maps to, not a raise you collect for holding the credential. The only computed ratio anywhere on this site is exam cost as a percent of the occupation's median monthly wage, the ranking metric behind the ROI Index, and it is fully derived from the two verified inputs above: nothing about it implies a wage outcome.

Refresh calendar

Vendor exam costs and renewal terms are re-checked on a quarterly cycle, since vendors change pricing and renewal requirements without warning and a number that was correct in January can be stale by the following quarter. BLS OEWS occupation data is refreshed annually, each spring, when the Bureau publishes its next May-reference-period estimates. Both refresh dates are reflected in the affected page's last_verified date the same day the check happens.

Schema validation and build gates

Every certification, comparison, and guide is a Markdown file whose frontmatter is validated against a strict schema at build time: missing fields, a malformed SOC code, or a cost that is not a number fails the build rather than shipping a broken page. The BLS occupation dataset gets the same treatment through a prebuild data-validation script that checks every wage record's SOC code format, required fields, and source URL before the site is allowed to build at all. Bad data cannot reach production; it can only fail the build.

Corrections

If a figure does not match its source, or a vendor has changed a price or a renewal term since our last check, use the contact form. See the editorial policy for how corrections get handled.