Table 3.
Reported effect size data on the relationship between indicators of deliberate practice and objective measurement of musical achievement.
| ID | Study design | Effect size data | ||||||
|---|---|---|---|---|---|---|---|---|
| Sample | Predictor | Performance measure | Sig. report | Reliability* | ||||
| n | r | p | rxx | ryy | ||||
| Kornicke, 1992 | College level pianists | Composite number of pieces sight-read | Expert rating of sight-reading performance | 73 | 0.50 | 0.99 | ||
| Ericsson et al., 1993—study II | University music majors (pianists) | Accumulated practice | Evenness of inter-onset intervals | 24 | −0.857 | <0.01 | ||
| Lehmann and Ericsson, 1996 | University music students | Accompanying score | Number of correctly performed notes | 16 | 0.72 | <0.01 | ||
| Krampe and Ericsson, 1996—study I+ | Beginning to professional pianists | Accumulated practice (until age of 20) | Evenness of inter-onset intervals | 48 | −0.62 | <0.01 | 0.97 | |
| Hallam, 1998 | Beginners | Accumulated practice time | Associated board of the royal schools music (ABRSM) | 109 | 0.67 | <0.01 | ||
| Meinz, 2000 | Beginning to advanced pianists | Number of accompanying performances | Expert rating of sight-reading performance | 107 | 0.57 | <0.01 | ||
| Tuffiash, 2002 | Undergraduate music and non-music majors | Cumulative piano accompaniment performances | Expert ratings of music performances | 135 | 0.426 | <0.01 | 0.91 | 0.75 |
| McPherson, 2005 | Beginners | Accumulated practice time (over 3 years) | Expert rating of performed rehearsed music | 99 | 0.568 | <0.01 | 0.92 | |
| Jabusch et al., 2007+ | School-aged children | Accumulated practice time | Evenness of inter-onset intervals | 30 | −0.46 | <0.05 | ||
| Kopiez and Lee, 2008 | Piano major students and graduates | Accumulated sight-reading expertise (until age of 18) | Sight-reading achievement | 52 | 0.359 | <0.01 | ||
| Jabusch et al., 2009+◦◦ | University music students | Life-time deliberate practice | Evenness of inter-onset intervals | 19 | −0.44 | <0.01 | ||
| Meinz and Hambrick, 2010◦◦◦ | Beginners to advanced pianists | Accumulated accompaniments and hours of deliberate sight-reading practice | Expert rating of sight-reading performance | 57 | 0.56 | <0.01 | 0.99 | |
| Kopiez et al., 2012—Study II+◦ | University music students (piano major) | Accumulated practice time | Evenness of inter-onset intervals | 19 | −0.42 | <0.05 | ||
Absolute values were used in meta-analysis.
Aggregated correlation based on all four correlations between accumulated deliberate practice and outcome variable.
Aggregated correlation based on two reported correlations between accumulated life-time deliberate practice and outcome variable.
According to Lehmann and Ericsson (1996) the mean correlation of accompaniments (r = 0.63) and hours of deliberate sight-reading practice (r = 0.48) was used as task-specific predictor for sight-reading performance.
Reliability coefficients reported in studies; assumed reliability (if not reported) of predictor variable used for attenuation correction in meta-analysis: rxx = 0.89; assumed reliability (if not reported) of outcome variable (ryy) for attenuation correction in meta-analysis: Ericsson et al., 1993 (ryy = 0.91), Lehmann and Ericsson, 1996 (ryy = 0.88), Hallam, 1998 (ryy = 0.91), Meinz, 2000 (ryy = 0.96), Jabusch et al., 2007 (ryy = 0.91), Kopiez and Lee, 2008 (ryy = 0.88), Jabusch et al., 2009 (ryy = 0.91), Kopiez et al., 2012 (ryy = 0.91).