MethodologyMeasuresConcept
Effective dates
When an enacted law takes effect, how CapitolMath works it out from the enacted text and each state's rules, and how its accuracy is checked.
An enacted bill's effective date is when it becomes law in practice. CapitolMath works it out for every enacted bill in the jurisdictions below and shows how it got there, beside the date.
Where it's available#
Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming and Congress, for laws enacted in their 2025 and 2026 sessions; Louisiana's, Maine's, Maryland's, Michigan's, Mississippi's, Montana's, Nebraska's, Nevada's, New Mexico's, North Carolina's, North Dakota's, Oregon's, South Carolina's and South Dakota's since 2023; and New Jersey's since its 2022–23 session. That is every state and Congress, each one dated only after passing the same accuracy check (see below).
What the date is#
- The main provisions' date. Many acts take effect in stages. CapitolMath's date is when the act's main provisions take effect, the date most readers mean by "when does this law take effect". The rest of the act is shown beside it.
- Staggered acts are marked. An act whose provisions take effect on different dates is marked staggered, and each dated provision is listed under Provisions with separate effective dates.
- Dates are the jurisdiction's own. "Today" is today where the law was enacted, and a law taking effect today has taken effect.
How it's worked out#
- A date the legislature publishes comes first. Florida and Ohio, for instance, publish each law's effective date. That date is used as published, and the law's text is still read, so a part that takes effect on another date is listed, and a text that disagrees with the published date says so.
- The enacted text is read for its own dates. An AI model reads every sentence of the enacted text that could set a date ("This act shall take effect July 1, 2026", "on the ninetieth day after it shall have become a law"). Each clause it finds must be quoted from the stored text word for word; one that isn't is discarded.
- Counted dates come from the record. A clause that counts from an event ("90 days after enactment") is counted from that event's date in the bill's history: the signature, the final vote or the session's adjournment.
- Otherwise, the jurisdiction's default rule. An act that names no date takes effect under its state's constitution or statutes, for example California's January 1 following a 90-day wait (Cal. Const. art. IV §8(c)). Each rule is cited with the date.
- References to other laws are followed. An act that takes effect "on the same date as chapter 711 of the laws of 2025" takes that law's date. One conditioned on another bill becoming law holds only if that bill did. A later act that changes the date is shown as the change, with the date it replaced.
How sure the date is#
| State | Means |
|---|---|
| Published | The legislature publishes this date itself. |
| Stated | The enacted text names this date. |
| Derived | Counted from a recorded event, by the text's own clause or the state's default rule. |
| Contingent | The text ties the date to something outside the legislative record, so no date is given. |
| Unresolved | Not enough is recorded to give a date. What is missing is shown. |
A provisional date counts from an estimate, usually a session's scheduled adjournment before the actual one is recorded. It's marked, and updates when the actual date arrives.
How its accuracy is checked#
Before a jurisdiction's dates are shown, a random sample is checked by hand against the enacted texts: 60 dated laws (all of them, where fewer exist) and the laws left undated. A jurisdiction goes live only with at most one wrong date in that sample, at least 75% of its enacted laws dated, and few undated laws a careful reader could have dated. The thresholds were set before any checking began.
After launch, 10 laws per jurisdiction are checked each quarter. A wrong date reopens the check for that jurisdiction.
When a date changes#
A date can change when an input arrives (an adjournment is recorded, a later act changes the date) or when CapitolMath corrects one. Either way the old date is kept, not overwritten. Record history on the bill shows what changed and when.
Where you'll see it#
- On the bill. Takes effect, under Progress, and a second line on the outcome chip: "takes effect Jan 1, 2027" or "in effect since Jul 1, 2026". See Reading a bill.
- In the bill list. The Takes effect and Takes Effect Basis filters, and a sortable Takes effect column in the table. See Bill facets.
- In the API, the MCP server and the bulk datasets. Each bill in
/v1/bill-searchcarrieseffective, its next and last effective dates and basis, and/v1/bill-detailthe full record: each provision's date and how it was worked out. Filter a search withtakes-effect-window,takes-effect-fromandtakes-effect-to, andeffective-status; the MCP server'ssearch_recordsandget_record, for bills, take and return the same. The Effective dates dataset has every date as a row, with its basis, joining to Bills by jurisdiction, session and bill number. See the API reference.