Authoritative post‑election tallies for the 2024 U.S. Senate elections show Republicans ending with 53 Senate seats, not 54. The official 2024 Senate elections summary lists the post‑election composition as 53 Republicans, 45 Democrats, and 2 Independents, with the Independents caucusing with Democrats, yielding a 53–47 functional split in favor of Republicans.(en.wikipedia.org)(congress.gov)(everycrsreport.com) Independent roundups (e.g., CBS News and other national outlets) likewise describe GOP control as a 53‑seat majority, not 54.(cbsnews.com)(grokipedia.com)

Moreover, Congressional Research Service profiles of the 119th Congress confirm that the Senate has 53 Republicans, 45 Democrats, and 2 Independents who both caucus with the Democrats; there is no indication of any party switch or GOP‑caucusing independent that would have taken the Republican caucus to 54 at any point during that period.(congress.gov)(senate.gov)

Since the predictor said the final counts in the remaining undecided races would bring the Republican caucus to 54 seats within about a week of November 8, 2024, and the caucus in practice stabilized at 53, the prediction did not come true.