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Stock-Based Compensation (Tables)
 6 Months Ended
Jul. 04, 2021
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions The fair value was estimated using the Monte Carlo simulation model with the following assumptions:
 
 
  
For the Six Months

Ended
 
  
July 4,

2021
 
June 28,

2020
Risk-free interest rate
    0.2%   1.5%
Teradyne volatility-historical
    43.9%   34.9%
NYSE Composite Index volatility-historical
    22.9%   11.4%
Dividend yield
    0.4%   0.6%
Fair Value of Stock Options Using Assumptions
The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:
 
 
  
For the Six Months Ended
 
  
July 4, 2021
  
June 28, 2020
Expected life (years)
    5.0   5.0
Risk-free interest rate
    0.4%   1.6%
Volatility-historical
    37.8%   31.6%
Dividend yield
    0.4%   0.6%