One thing to keep in mind, is that it was a long time before people realized Socialism as implemented had serious economic efficiency issues. For example, leading American economist Paul Samuelson projected that the Soviet economy would overtake the US by the mid 1980s, and his textbook (which until quite recently was the standard) had the Soviet Union surpassing the US economically until well into the 1980s. For technical reasons (that I can describe in detail if you want), measuring GDP all but impossible in non-market economies. The technocrats (and in a lot of ways the USSR was an astonishingly technocratic state) who were in charge of measuring output lived well, extreme deprivation was rare, and the state could achieve rough military parity with the US. Much of the serious inefficiencies were not understood until much later.

However, to answer the question there were academic economists who noticed the problems of the communist system. The most important, in my opinion was Janos Kornai, a Hungarian economist. His big contribution to economics (both communist and free market) was the idea of the soft budget constraint. To simplify, it's the idea that if you keep lending money to an inefficient firm, it will never improve it's performance because it never has to. Janos Kornai's thoughts were hugely influential in the reforms carried out by Deng Xiaoping in China.As far as the career of Janos Kornai is concerned, he did suffer for not being sufficiently gung-ho about communism. For example, he was sacked in 1955 from being the editor of the communist party newspaper for his lack of communist feeling. That said, he had a long and presigious career in academia. He published many books before he emigrated to the US, including the Economics of Shortage in 1980 that really questioned a lot of communist assumptions about the world.

Another example is that of Yegor Gaidar. Gaidar was a Soviet trained economists who was key for the "Shock Therapy" reforms of the early 1990s and much of his reform showed how in his view, reforming communism wasn't possible. Anatoly Chubais, probably the second most important reformer, started out as a proponent of "Market Communism" similar to what you saw in Yugoslavia, but eventually came out to be a key implementer of "Shock Therapy". That said, both worked on That said, he worked for the Political Bureau Commission on Improvement of Administration of National Economy , an agency that during the 1980s was tasked with implementing moderate reforms, similar to what you had in Hungary or Yugoslavia, all of this done with the direct support of senior members of the Communist party.

More broadly speaking, the Soviet Union had a desperate need for accurate statistics. Especially post-Stalin, there was always a certain level of toleration of internal critique, so long as it was kept outside of the broader public sphere, and never openly calling for the end of Communist rule.

Thanks for the great responses! I’ll definitely check out the study.