Not all pollsters were predicting a slim Paul Vallas victory going into the April 4 mayoral runoff. IZQ Strategies had Brandon Johnson in the lead — and by an eye-opening 5 percentage points. Once mail-in votes were tabulated, that forecast wasn’t far off: Johnson wound up with 52.1 percent of the vote to Vallas’s 47.9.

What is IZQ? It’s a firm founded in 2021 by Gustavo Sánchez, a 29-year-old Chicagoan of Puerto Rican descent who specializes in surveying difficult-to-interview Latino voters. “I’m the bilingual pollster” is how Sánchez, who grew up in St. Louis and studied political science at the University of Chicago, sums up his specialty.

Skeptical of mayoral polls he was seeing, Sánchez raised $809 on GoFundMe toward conducting his own, released April 3. His results showed Vallas winning the white vote by 10 points, lower than conventional wisdom had it. But his most significant assertion, based on voter history in the 2019 election and this year’s first round, was that only 61 percent of voters would be over 45 years old — an age group that favored Vallas.

“A lot of people were surprised at the age weighting,” Sánchez says. “There was a lot of ridicule, but I only had to wait a day to be right.”