  Many studies of possible new physics employ effective field theory (EFT),
whereby corrections to the Standard Model take the form of higher-dimensional
operators, suppressed by a large energy scale. Fits of such a theory to data
typically use parton level observables, which limits the datasets one can use.
In order to theoretically model search channels involving many additional jets,
it is important to include tree-level matrix elements matched to a parton
shower algorithm, and a suitable matching procedure to remove the double
counting of additional radiation. There are then two potential problems: (i)
EFT corrections are absent in the shower, leading to an extra source of
discontinuities in the matching procedure; (ii) the uncertainty in the matching
procedure may be such that no additional constraints are obtained from
observables sensitive to radiation. In this paper, we review why the first of
these is not a problem in practice, and perform a detailed study of the second.
In particular, we quantify the additional constraints on EFT expected from top
pair plus multijet events, relative to inclusive top pair production alone.
