Short answers, pulled from the story.
The Era of Stagnation covered the period from 1964, when Leonid Brezhnev became Soviet leader, to 1985, when Mikhail Gorbachev took power. It also encompasses the short tenures of Yuri Andropov, who led the Soviet Union from 1982 to 1984, and Konstantin Chernenko, who held power from 1984 to 1985. Most scholars place the beginning of economic stagnation specifically around 1975, though some date it as early as the 1960s.
Mikhail Gorbachev coined the term 'Era of Stagnation' in the 1980s to describe the economic difficulties that developed under Leonid Brezhnev. After becoming Soviet leader, Gorbachev characterized the Brezhnev economy as 'the lowest stage of socialism.'
Historians have proposed several causes, including high military expenditure, the centralized planning system's inability to permit rapid innovation, and the Soviet Union's growing technological gap with the West. The 1973 oil crisis temporarily masked structural problems by boosting petroleum revenues, but the underlying issues remained. Gregory Grossman's research also pointed to the rapid growth of unofficial shadow markets during the 1970s and 1980s, which distorted central planning in ways Gosplan could not account for.
Researcher Elizabeth Brainerd found that child height halted or slightly regressed in the early 1970s, and birth weights declined from 1970 onward. Life expectancy gaps between Soviet and American citizens widened sharply: in 1965, male life expectancy in the Soviet Union fell below that of American men by only 2.5 years, but by 1980 the gap had grown to nearly 8.5 years for men and 4.3 years for women.
Alexei Kosygin, the Chairman of the Council of Ministers, introduced a reform in 1965 that aimed to improve the planned economy within a socialist framework, borrowing elements from Western practice including the concept of profit-making. During the Eighth Five-Year Plan from 1966 to 1970, the reform produced large-scale land reclamation programmes and new irrigation infrastructure. Historians consider the reform to have failed overall, calling its link to the period's high growth rates 'tenuous,' and Kosygin's more ambitious subsequent proposals were halted in 1971.
Prominent dissidents included nuclear physicist Andrei Sakharov and Soviet Army General Pyotr Grigorenko, both well-known representatives of open political opposition. Writers Viktor Astafyev and Oles Honchar, playwright Grigory Gorin, and directors Eldar Ryazanov and Mark Zakharov criticized the era's social and moral conditions without directly confronting political authority. Eight protesters who demonstrated in Red Square in Moscow against the Warsaw Pact invasion of Czechoslovakia were subsequently imprisoned.