Here one can see the cross-sectional effects of phonological awareness and morphological awareness on kanji. Notice that in the case of phonological awareness, the effect is fairly weak and invariant across quantiles.
However, one can see that the relationship is quite dynamic for morphological awareness. For poor readers, this relationship is unstable (the bottom line). For average readers, the association resembles a slightly positive and monotonic relationship. But most interestingly, the association for excellent readers takes on an exponential relationship.
For hiragana the influence of phonological awareness is fairly consistent and linear, but has subtle increases by quantile. Poor readers have the weakest assocations, followed by slightly stronger associations for average readers, then followed by association increases in excellent readers.
The associations change to a degree for morphological awareness. Morphological awareness seems to have a more consistent, linear, and positive relationship with hiragana.
We may first inspect the longitudinal plots for Year 4 kanji scores. Phonological awareness has essentially no association with kanji for excellent readers, but for poor and average readers, the association is positive until hitting a certain threshold, thereafter it ceases to be predictive of reading ability.
For morphological awareness, the association is more consistently linear, but the association weakens as expertise in kanji is gained. For weak readers, the assocation starts off poor and then gradually becomes stronger and more linear. For average readers, the association is more consistent. For excellent readers, there is only a slightly positive assocation.
Examining the hiragana plots, we can see the magnitude between phonological awareness and Year 4 hiragana fluency scores increases by skill level. There seems to be essentially no association for poor readers, some assocation for average readers, and a stronger association for excellent readers.
Finally, the assocations are more subtle for morphological awareness, but generally not as magnified as morphological awareness. For poor and average readers, there is little effect, but after hitting above average scores in morphological awareness, the association seems to increase to a degree. The association is weak but consistent for excellent readers