social security system

Discuss the equity and efficiency effects of the following recent and proposed changes in the social security system and, where appropriate, provide alternative reforms directed at the same objective:
a Changing the formula by which social security benefits are calculated to reflect total contributions, not just the contributions in a limited number of years.
b Tougher eligibility standards for disability payments.
c Increasing the eligibility age for social security benefits.
d Increasing benefits for those who retire later so that they receive the same expected present discounted value of benefits, regardless of age of retirement.
e Exempting those over the age of 65 from paying social security taxes.
f Lowering the cost of living adjustment for social security benefits.