Short answers, pulled from the story.
A defined benefit plan pays a retirement income calculated by a fixed formula based on salary and years of service, with the employer bearing the investment risk. A defined contribution plan sets aside a fixed percentage of earnings into an individual account, and the retirement payout depends entirely on how much was contributed and how the investments performed.
Augustus Caesar introduced one of the first recognizable pension schemes in 13 BC, guaranteeing retired Roman soldiers a lump sum of at least 3,000 denarii after sixteen years of service in a legion. That amount represented roughly thirteen times a legionnaire's annual salary.
Germany was the first country to introduce a universal pension program for employees. Otto von Bismarck's Old Age and Disability Insurance Bill was enacted in 1889, originally providing benefits to workers who reached the age of 70, a threshold later lowered to 65 in 1916.
The gender pension gap is the difference between men and women in average pension income. In OECD countries between 2013 and 2018, the gap ranged from 3 percent in Estonia to 47 percent in Japan. Women also spend more years in retirement on average, at 22.8 years compared to 18.4 years for men, according to 2022 OECD data.
The Northern Mariana Islands Retirement Fund filed for Chapter 11 bankruptcy protection in April 2012, carrying only $268.4 million in assets against $911 million in liabilities. The fund experienced low investment returns and a benefit structure that had been increased without corresponding increases in funding.
A pay-as-you-go pension system funds current retirees directly from the contributions of current workers rather than from invested reserves. Germany, France, Italy, and Spain operate largely unfunded social security systems on this basis. The sustainability of these systems depends on the ratio of working adults to retirees, which is narrowing in most developed countries as birth rates fall and life expectancy rises.