in the escape fraction of ionizing photons can explain the observed drop with a mild increase in the neutral fraction of $\Delta x_{\rm H\,{\sc I}} =$ 0.1–0.2, and @bolton13 argued that the rise of the neutral fraction of only $\Delta x_{\rm H\,{\sc I}} =$ 0.1 by $z=7$ is sufficient when accounting for self-shielding absorption systems (Lyman limit systems; LLSs) in the IGM, which are expected to be abundant near the end of reionization (though see @mesinger15). At $z \sim 7$, a sufficient sample has been assembled to start discerning between ‘patchy’ and ‘smooth’ models of Ly$\alpha$ attenuation. @pentericci14 found from a compilation of observations at $z \sim 7$ that the ‘patchy’ model of Ly$\alpha$ attenuation (which does not necessarily literally mean a patchy reionization process but may instead signal the abundant LLSs; @mesinger15), is favored over the ‘smooth’ attenuation model. Although the interpretation is not straightforward, these studies all highlight the potential of studying the Ly$\alpha$ fraction as a valuable probe of reionization.

[lccccccccc]{} z8\_GSD\_17938 & 3:32:49.94 & $-$27:48:18.1 & 25.7 & 25.7 & $-$21.6 & 8.07 & $[7.87, 8.37]$ & 0.70 & $<$ 12\
z7\_GSD\_10175 & 3:32:50.48 & $-$27:46:56.0 & 25.7 & 25.6 & $-$21.2 & 6.93 & $[6.14, 