Table 3.
Average Weighted Effect Sizes and Relevant Statistics for Studies Providing Only Alphabet Instruction
| Type of instruction | k | n | Average weighted effect size |
95% CI |
τ2 | Homogeneity of effect sizes |
File drawer statistic |
||
|---|---|---|---|---|---|---|---|---|---|
| Lower bound | Upper bound | Q | p | ||||||
| Letter name knowledge outcomes | |||||||||
| Full sample | 8 | 389 | 0.14 | −0.10 | 0.37 | 0.02 | 8.16 | .319 | |
| Studies providing LN instruction | 1 | 28 | 0.00 | −0.86 | 0.86 | ||||
| Studies providing LS instruction | 2 | 172 | 0.08 | −0.22 | 0.39 | 0.00 | 0.12 | .731 | |
| Studies providing LN and LS instruction | 5 | 189 | 0.23 | −0.20 | 0.67 | 0.12 | 7.75 | .101 | |
| Letter sound knowledge outcomes | |||||||||
| Full sample | 4 | 856 | 0.48 | 0.40 | 0.55 | 0.00 | 2.57 | .462 | 20 |
| Studies providing LN instruction | 1 | 628 | 0.50 | 0.34 | 0.66 | 9 | |||
| Studies providing LS instruction | 2 | 204 | 0.24 | −0.04 | 0.53 | 0.00 | 0.19 | .661 | |
| Studies providing LN and LS instruction | 1 | 24 | 0.41 | −0.40 | 1.22 | ||||
| Letter writing outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LS instruction | 1 | 112 | 0.31 | −0.06 | 0.68 | ||||
| Letter name fluency outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LN instruction | 1 | 39 | 0.64 | 0.00 | 1.28 | ||||
| Letter sound fluency outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LS instruction | 1 | 34 | −0.33 | −1.01 | 0.35 | ||||
| Immediate phonological awareness outcomes | |||||||||
| Full sample | 6 | 829 | −0.17 | −0.73 | 0.40 | 0.44 | 59.56 | < .001 | |
| Studies providing LN instruction | 1 | 516 | 0.62 | 0.44 | 0.79 | 11 | |||
| Studies providing LS instruction | 4 | 284 | −0.22 | −0.76 | 0.33 | 0.26 | 17.24 | .001 | |
| Studies providing LN and LS instruction | 1 | 29 | −0.98 | −1.75 | −0.20 | 1 | |||
| Immediate reading outcomes | |||||||||
| Full sample | 6 | 397 | 0.21 | 0.02 | 0.40 | −0.01 | 4.60 | .467 | 1 |
| Studies providing LN instruction | 1 | 39 | 0.49 | −0.14 | 1.13 | ||||
| Studies providing LS instruction | 5 | 358 | 0.18 | −0.03 | 0.39 | 0.00 | 3.74 | .442 | |
| Immediate spelling outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LS instruction | 1 | 112 | 0.30 | −0.08 | 0.67 | ||||
| Follow-up phonological awareness outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LS instruction | 3 | 264 | 0.01 | −0.80 | 0.82 | 0.46 | 20.57 | < .001 | |
| Follow-up reading outcomes | |||||||||
| Full sample | 4 | 285 | 0.11 | −0.12 | 0.35 | 0.00 | 2.11 | .550 | |
| Studies providing LN instruction | 1 | 39 | 0.25 | −0.38 | 0.88 | ||||
| Studies providing LS instruction | 3 | 246 | 0.09 | −0.15 | 0.34 | 0.00 | 1.91 | .384 | |
| Follow-up spelling outcomes | |||||||||
| Full sample | |||||||||
| Studies providing LS instruction | 3 | 264 | 0.14 | −0.62 | 0.89 | 0.40 | 18.20 | < .001 | |
Note, k = number of independent contrasts/studies; n = total number of children; CI = confidence interval; τ2 = between-study variability; LN = letter name; LS = letter sound.