Figure 1. Bimodal vs unimodal models of cassette exon splicing.

In the bimodal model, some cells consistently splice in the exon, while others consistently skip it. After mRNA capture and sequencing, observations of $\mathrm{\Psi }$ are almost exclusively binary. In the unimodal model, individual cells express some mRNAs that splice in the cassette exon and some that skip it. Low mRNA capture dramatically reduces the number of cells in which both isoforms are observed, artificially inflating binary $\mathrm{\Psi }$ values.