Lael Brainard, a governor for the Federal Reserve, confirmed on April 5 that the metrics used to measure inflation obscure the fact that low-income families are being hurt the most.

According to Brainard, alongside the fact that poor families purchase vastly different goods than rich households, the categories used to judge inflation also group together luxury goods and essentials, hiding the true rate of inflation on the low end.

Brainard, who has been tapped to be the net Fed vice-chair by President Joe Biden, spoke about the urgent need to bring inflation under control during a speech she gave on Tuesday.

While high-income households spend less than one out of every three dollars they earn on necessities, in low-income households that number jumps to more than three dollars out of every four. Because of that vulnerability, low-income families aren't able to avoid increasing prices in the same way that high-income families can.

Part of the reason why this vulnerability is difficult to gauge is the way that inflation is measured: rather than being an average of the percentage increase in price across all goods, items that Americans spend more of their money on carry more weight in the analysis.

Ideally, this measurement should result in essential things like energy, groceries, and clothing being the primary driving force since those are the areas where low-income families spend the majority of their money. In practice, however, this weighted analysis results in luxury goods like caviar being grouped in the same category as canned tuna.

"Households with different levels of income may purchase significantly different items even within the same elementary index categories for goods and services," Brainard said, specifically pointing to the caviar and tuna example.

This grouping creates a major problem: while the price of tuna may shoot up during a fish shortage, for example, the price of caviar can remain more stable thanks to its higher profit margins. Higher-income families may also have more alternatives to the higher-priced goods compared to their lower-income counterparts.

While rich families can simply skip out on a luxury item, low-income families are faced with shrinking options for affordable essentials.

"A household that had been purchasing brand-name cereal could save money by purchasing store-brand cereal instead, perhaps even eliminating any effect of the price increase on their actual spending while purchasing the same quantity of cereal," Brainard said.

Of course, switching to a cheaper alternative isn't an option for families already purchasing the cheapest products.

In addition to expressing concerns over the obscured effects of inflation on poor Americans, Brainard also said that she expects inflation to continue, potentially into the summer months.

"Currently, inflation is much too high and is subject to upside risks," Brainard said. "The committee is prepared to take stronger action if indicators of inflation and inflation expectations indicate that such action is warranted."

"It is of paramount importance to get inflation down," she continued.

Brainard said that she expects the Fed to initiate more interest rate increases in the coming months, alongside a rapid reduction of the Fed's $9 trillion balance sheet.

"Given that the recovery has been considerably stronger and faster than in the previous cycle, I expect the balance sheet to shrink considerably more rapidly than in the previous recovery, with significantly larger caps and a much shorter period to phase in the maximum caps compared with 2017-19," Brainard said.

Brainard's position has Wall Street investors worried about "the speed and aggressiveness of the Fed with its balance sheet reductions", according to CFRA Research's Sam Stovall.