Technical errors and coverage in single-cell sequencing data. (a) Technical errors that occur in single-cell sequencing (SCS) data include: false-positive errors, allelic dropout events and false-negative errors due to insufficient coverage. ‘Pop’ indicates a population of cells. (b) Coverage metrics in SCS data include coverage depth and total physical coverage, or breadth. (c) Coverage uniformity, or ‘eveness’ in SCS data can vary from cell to cell, but is often more uniform in standard genomic DNA sequencing experiments using populations of cells.