Since May 2013, when CBO issued its previous baseline budget
projections, the agency has reduced its estimate of this year’s deficit
by $46 billion and raised its estimate of the cumulative deficit between
2014 and 2023 by $1.0 trillion. (That 10-year period was the one
covered by the previous baseline.) Those changes result from revisions
to CBO’s economic forecast; newly enacted legislation; and other,
so-called technical factors, such as new information about recent
spending and tax collections.