Bernhardt ( 2005 ) reviewed threshold studies involving multiple L1 groups, L2s, literacy levels, and demographic factors. She calculated that measured L1 reading skill accounted for 14 percent to 21 percent of the variance in L2 reading measures, whereas L2 linguistic knowledge accounted for 30 percent of the variance, accounting for a total of about 50 percent. These calculations leave the other 50 percent of the variance in L2 reading measures unexplained. Bernhardt (2005) suggested that comprehension strategies, reader interest, reader engagement, content knowledge, and motivation might collectively address this wide gap, as illustrated in her compensatory model of L2 reading.
