Evidence from multiple post‑debate polls shows that Nikki Haley—not Vivek Ramaswamy—had the largest positive bounce in support after the first GOP primary debate on August 23, 2023.

Key points:

• A FiveThirtyEight/Washington Post/Ipsos panel of likely GOP primary voters before and after the debate found that among debate watchers, the share considering voting for Haley jumped far more than for any other on‑stage candidate (from about 30% pre‑debate to 47% post‑debate, a 17‑point gain). Ramaswamy’s "would consider" support rose only modestly by comparison. (ipsos.com)
• A summary of national polling averages from RealClearPolitics for the two weeks after the debate (Aug 23–Sept 6) shows Haley’s vote share increasing by about 2.9 percentage points—the largest gain among debate participants—while Ramaswamy’s support actually declined slightly over the same period. (en.wikipedia.org)
• FiveThirtyEight’s analysis of Ramaswamy’s trajectory noted that while the debate boosted his profile and favorability among some Republicans, his unfavorable ratings rose even more, limiting any net positive "bounce" in overall support. (fivethirtyeight.com)
• A separate Reuters/Ipsos survey right after the debate found significant numbers of Republicans saying they were more likely to consider DeSantis and Ramaswamy, but this did not translate into Ramaswamy clearly surpassing all other on‑stage candidates in sustained polling gains; Haley still showed the clearest improvement in multiple support metrics. (ipsos.com)
• Ramaswamy did dominate attention metrics—e.g., he generated the most Google searches of the on‑stage candidates during and immediately after the debate—but those spikes in online interest did not correspond to the largest increase in actual voter support. (washingtonpost.com)

Because the best available polling and "voters considering" data show Haley, not Ramaswamy, getting the biggest post‑debate boost in support, Sacks’s prediction that Vivek would have "the biggest bounce out of the debate" is best judged as wrong, even though Ramaswamy clearly drew a great deal of attention.