We have used Monte Carlo simulations to evaluate electron-electron (e-e) interactions in multibeam lithography columns. For a linear array of 32 beams with variable length from 40 to 400 mum at the photocathode, the spot size and placement were calculated for total beam currents of up to 800 nA at the substrate. In general, the e-e interactions are reduced when the linear array size is increased, therefore reducing the total beam blur. However, this is not true for placement errors induced by e-e interactions, specifically when the absolute magnitude of the error at the edge of the array is considered. We have used a multibeam test bed, equipped with a magnification stack for high spatial resolution imaging of the photoemission, to evaluate experimentally the effect of e-e interactions.