Studies with a listed included-status location

Recruiting, not yet recruiting, or enrolling by invitation · unique NCT IDs per state

California5,310
Texas4,654
New York4,295
Florida3,713
Ohio3,034
Includes upcoming and invitation-only enrollment. States overlap; counts are neither sites nor open seats.

California appeared on 5,310 study records with at least one listed site whose location status was recruiting, not yet recruiting, or enrolling by invitation in a MedDataUSA snapshot of ClinicalTrials.gov. Texas followed with 4,654 and New York with 4,295.

Those are study–state counts, not open enrollment slots. They do not say how many participants a site can accept, whether a person qualifies, or whether the registry status still matches today's phone call.

Quick read

  • The API query returned 27,220 studies whose overall status was recruiting, not yet recruiting, or enrolling by invitation and whose records matched the United States.
  • For 5,302 of those records, the extracted locations did not include a U.S. location carrying one of the same three included statuses.
  • A study can count in multiple states, but only once within a state. State counts therefore overlap and must not be summed as a national study total.

Overall status is not site status

A multisite study can be recruiting overall while a particular location is completed, withdrawn, suspended, or no longer recruiting. It can also retain U.S. locations without one of the three included statuses in the extracted record.

That is why this analysis did not count every state named on a study with an overall recruiting label. It required the individual location to carry one of three statuses: recruiting, not yet recruiting, or enrolling by invitation. “Not yet recruiting” is upcoming rather than currently open, and “enrolling by invitation” is not general public recruitment, so the combined category must not be read as a count of sites actively accepting anyone who inquires.

The 5,302-record gap between the overall query and the presence of a qualifying U.S. site is not proof of bad data. It can reflect removed or inactive U.S. locations, studies recruiting only outside the United States, missing site-status fields, or the difference between record-level search matching and the final analytic rule.

The leading states

After California, Texas, and New York, the highest study–state counts were Florida at 3,713, Ohio at 3,034, Pennsylvania at 3,010, Massachusetts at 2,971, Illinois at 2,514, North Carolina at 2,429, and Maryland at 2,411.

Population, research institutions, sponsor networks, specialty centers, and disease mix all influence those totals. A raw count is not a per-capita access ranking, and state borders can obscure travel markets.

Why a registry count is not capacity

ClinicalTrials.gov records are submitted and maintained by responsible parties. A location can stop enrolling before a status update reaches the public record. Some trials recruit by referral or invitation. Eligibility criteria can sharply narrow the pool even when a site is open.

The registry also does not publish a standardized count of remaining seats at each site. Enrollment is usually a study-level target or actual count, not a live local inventory.

A responsible search workflow

Patients and clinicians should treat registry results as leads. Confirm the study status, read eligibility criteria, check the last update date, and contact the site or study team. Researchers comparing geographies should freeze a retrieval timestamp, deduplicate NCT identifiers—the registry's unique study IDs—within each geography, and state whether they used overall or location-level status.

Methodology and limitations

MedDataUSA used ClinicalTrials.gov API v2 to retrieve all 27,220 records returned on October 7, 2026 for U.S.-matching studies with overall status Recruiting, Not yet recruiting, or Enrolling by invitation. We paged through the complete result, verified the returned total, and retained NCT ID, overall status, and U.S. location state/status.

For each study, we counted a state once when at least one U.S. location in that state had one of the same three included statuses. Counts overlap across states. We did not geocode locations, calculate per-capita rates, test eligibility, measure open seats, or independently contact sites. This is a time-stamped registry analysis, not clinical advice.

Sources