What Works for Children with Literacy Difficulties? - Digital ...

Average pre-and post-test raw scores and gains for writing, and s.d’s of pre-and posttest
score (s.d’s of gains not stated), statistical significances, and effect sizes calculated
(by GB) using this formula: difference in gains (experimental group’s gain minus
relevant control group’s gain) divided by pre-test s.d. of relevant control group (source:
Sutherland and Topping, 1999, Table 1, p.170, edited and incorporating details from text):
Cross-ability Same-ability
Experimental Control Experimental Control
Pre-test
1.75 1.31 1.63 1.75
(0.97) (0.92) (0.78) (0.43)
ns ns ns
Post-test
2.13 1.44 1.69 1.56
(0.99) (0.79) (0.92) (0.61)
gain 0.38
p = 0.036
Ratio gain: n/a
0.13
0.06
ns
ns
ns p = 0.049
effect size = 0.27 effect size = 0.58
difference between gains of 2 experimental groups significant, p = 0.038
132
-0.19
ns