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The Cell barcode QA/QC task lets you filter barcodes to differentiate between barcodes added to cells and barcodes added to empty gems or droplets in determine whether a given cell barcode is associated with a cell. This is an important QC step in all droplet-based single cell RNA-Seq experiments. seq experiments, such as Drop-seq, where all barcodes are sequenced. 

To invoke Cell barcode QA/QC: 

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The Cell barcode QA/QC task report is a plot (Figure 1). Barcodes are ordered on the X-axis by the number reads so such that the barcode closest to the Y-axis has the most reads and the barcode furthest from the Y-axis has the fewest reads. The Y-axis value is the number of counts mapped reads corresponding to each barcode. This type of plot is often referred to as a knee plot. 

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