Data is from 2014. The family data is from the American Community Survey Family income by family, male householder, living alone and family with own children under 18 years. The income is then run though ADP's Salary Paycheck Estimator to find the approximate monthly take home pay.
All of the needs are calculated using EPI's Family Budget Calculator, except transportation, which is estimated using the price of a monthly transporatation pass in the location.
The guideline is adapted from Elizabeth Warren's book