Account value
Your member contributions plus interest. It is what a refund pays, not what your pension is based on.
Handbook pp. 7-8, p. 42More on this →Put the terms together in the TFFR calculator, or read how the benefit formula and tiers work.
Air time
Up to 5 years of service credit not tied to actual work, which can be bought after 5 years of TFFR service.
Handbook p. 14, p. 42More on this →Critical shortage area
A place or subject named each year by the Education Standards and Practices Board where retirees may work over the hour limit after a one-year wait.
Handbook p. 28More on this →Dual member
Someone with service in TFFR and the NDPERS defined benefit plan or the Highway Patrol Retirement System.
Handbook p. 4, p. 43More on this →Early retirement reduction factor
The permanent cut for starting before your unreduced date: 6% a year (Tier 1 Grandfathered) or 8% a year (Tier 1 Non-grandfathered and Tier 2).
Handbook p. 18; NDAC 82-05-04-01More on this →Final average salary (FAS)
The average of your 3 (Tier 1) or 5 (Tier 2) highest fiscal-year salaries, as a monthly amount.
Handbook p. 43; NDCC 15-39.1-10(2)More on this →Fiscal (plan) year
July 1 to June 30.
Handbook p. 13, p. 43More on this →Partial Lump Sum Option (PLSO)
A lump sum of 12 times the single life benefit at retirement, for members eligible for an unreduced benefit, in exchange for a smaller monthly benefit.
Handbook pp. 20-21More on this →Pop-up
Under a joint and survivor option, your benefit rises to the single life amount if your beneficiary dies first.
Handbook p. 19More on this →RIO
The North Dakota Retirement and Investment Office, which runs TFFR for the TFFR Board of Trustees. Phone 800-952-2970 or 701-328-9885; rio@nd.gov.
Handbook p. i, p. 2Rule of 85 / Rule of 90
When your age plus years of service equals 85 or 90 or more.
Handbook p. 44More on this →Service credit
1 year for 700 or more compensated hours in a fiscal year, a fraction for fewer, at most 1 a year.
Handbook p. 44More on this →Simplified General Rule
The IRS method for spreading your after-tax contributions over a set number of payments, so part of each payment is tax-free.
Handbook p. 24More on this →Single life annuity
The standard form of payment, the highest monthly amount, for your life only.
Handbook pp. 19-20; NDAC 82-05-02-01More on this →Tier 1 Grandfathered
A Tier 1 member who on June 30, 2013 was vested (3 years) and either at least 55 or had age plus service of 65 or more. Keeps the Rule of 85 and the 6% a year early cut.
NDCC 15-39.1-04(13); Handbook p. 45More on this →Tier 1 Non-grandfathered
A Tier 1 member who did not meet the grandfathering test on June 30, 2013. Uses the Rule of 90 with a minimum age of 60 and the 8% a year early cut.
NDCC 15-39.1-04(15); Handbook p. 45More on this →Tier 2
Members who joined on or after July 1, 2008, and returning members who took a refund after June 30, 2008. 5-year vesting and a 5-year final average salary.
Handbook p. 45; NDCC 15-39.1-04(16)More on this →Vested
Having the 3 (Tier 1) or 5 (Tier 2) years of service you need for a lifetime monthly benefit.
Handbook p. 46More on this →Source: Teachers' Fund for Retirement Member Handbook, 5/7/2026, pp. i, 2, 4, 7-8, 13, 14, 18, 19-20, 20-21, 24, 28, 42, 43, 44, 45, 46. Also: NDCC 15-39.1-04, 15-39.1-10; NDAC 82-05-02-01, 82-05-04-01. Last reviewed .