A computer-implemented method of visualizing differences between n-dimensional data sets, the computer-implemented method comprising: under control of one or more processing devices, concatenating a first data set of n-dimensional data and a second data set of n-dimensional data to obtain a concatenated data set, wherein the n-dimensional data comprises a plurality of events in a plurality of dimensions; performing dimensionality reduction on the concatenated data set to obtain a mapping of events in the first and second data sets: performing frequency difference gating on the mapping of events by: selecting a first and a second subset of n-dimensional data for comparison in response to user input; generating a multi-dimensional histogram with a plurality of elements per dimension according to a bivariate frequency estimate of each of the first subset and the second subset within the first data set and the second data set, the multi-dimensional histogram comprising a plurality of elements; normalizing the multi-dimensional histogram by event count; generating difference histograms for each element of the multi-dimensional histogram; and bi-normalizing the difference histograms wherein values corresponding to a region which has more events in the first subset are rescaled by a global positive rescaling factor, and values corresponding to a region which has more events in the second subset are rescaled by a global negative rescaling factor; generating a visualization from the frequency difference gating for display via a display device, the visualization showing regions in a multivariate space where a frequency of events from the first subset is different than a frequency of events from the second subset according to a defined threshold. concatenating a first data set of n-dimensional data and a second data set of n-dimensional data to obtain a concatenated data set, wherein the n-dimensional data comprises a plurality of events in a plurality of dimensions; performing dimensionality reduction on the concatenated data set to obtain a mapping of events in the first and second data sets: performing frequency difference gating on the mapping of events by: selecting a first and a second subset of n-dimensional data for comparison in response to user input; generating a multi-dimensional histogram with a plurality of elements per dimension according to a bivariate frequency estimate of each of the first subset and the second subset within the first data set and the second data set, the multi-dimensional histogram comprising a plurality of elements; normalizing the multi-dimensional histogram by event count; generating difference histograms for each element of the multi-dimensional histogram; and bi-normalizing the difference histograms wherein values corresponding to a region which has more events in the first subset are rescaled by a global positive rescaling factor, and values corresponding to a region which has more events in the second subset are rescaled by a global negative rescaling factor; generating a visualization from the frequency difference gating for display via a display device, the visualization showing regions in a multivariate space where a frequency of events from the first subset is different than a frequency of events from the second subset according to a defined threshold. performing frequency difference gating on the mapping of events by: selecting a first and a second subset of n-dimensional data for comparison in response to user input; generating a multi-dimensional histogram with a plurality of elements per dimension according to a bivariate frequency estimate of each of the first subset and the second subset within the first data set and the second data set, the multi-dimensional histogram comprising a plurality of elements; normalizing the multi-dimensional histogram by event count; generating difference histograms for each element of the multi-dimensional histogram; and bi-normalizing the difference histograms wherein values corresponding to a region which has more events in the first subset are rescaled by a global positive rescaling factor, and values corresponding to a region which has more events in the second subset are rescaled by a global negative rescaling factor; selecting a first and a second subset of n-dimensional data for comparison in response to user input; generating a multi-dimensional histogram with a plurality of elements per dimension according to a bivariate frequency estimate of each of the first subset and the second subset within the first data set and the second data set, the multi-dimensional histogram comprising a plurality of elements; normalizing the multi-dimensional histogram by event count; generating difference histograms for each element of the multi-dimensional histogram; and bi-normalizing the difference histograms wherein values corresponding to a region which has more events in the first subset are rescaled by a global positive rescaling factor, and values corresponding to a region which has more events in the second subset are rescaled by a global negative rescaling factor; generating a visualization from the frequency difference gating for display via a display device, the visualization showing regions in a multivariate space where a frequency of events from the first subset is different than a frequency of events from the second subset according to a defined threshold.