Key takeaway: We only publish a number we can link to, and we date every figure.
Where our numbers come from
We start with primary sources: the Hawaiʻi Department of Taxation, the Department of Labor and Industrial Relations, DBEDT, the four county real property tax offices, Hawaiian Electric and KIUC rate filings, HUD, the Bureau of Labor Statistics, the Census Bureau, the BEA and transit agencies. Where no agency publishes a number, we use reporting from local newsrooms such as Civil Beat, the Honolulu Star-Advertiser, Hawaii News Now, Maui Now and Hawaiʻi Public Radio, and we say so.
Showing every island
Costs in Hawaiʻi change a lot from one island to the next, so we report figures by island or county wherever a source allows. When a source covers only Oʻahu or only the state, we label it that way rather than applying it to every island. Molokaʻi and Lānaʻi are part of Maui County, so they share its tax rates and HUD rent figures, but we report their electricity and gas separately.
When sources disagree
Rent is the clearest example: HUD, Rentometer, RentCafe and Zillow each measure something different. When sources disagree, we show more than one and explain why, rather than picking the most dramatic number.
Our own calculations
Some figures, like a typical electric bill or a sample property tax bill, are our own arithmetic from published rates. We label these as our calculation and show the inputs.
How often we update
We recheck headline figures monthly and change the date when a number changes. Gas and electricity move every month; taxes and wages change on set dates, usually January 1 or July 1.
Corrections
If you see something wrong or out of date, tell us. We fix errors and note the change on the cost index page.