27.12.2013 Views

The influence of the place-value structure of the Arabic number ...

The influence of the place-value structure of the Arabic number ...

The influence of the place-value structure of the Arabic number ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

A word on <strong>the</strong> validity <strong>of</strong> <strong>the</strong> current study<br />

Although statistically reliable <strong>influence</strong>s <strong>of</strong> <strong>place</strong>-<strong>value</strong> understanding in first grade on<br />

arithmetic performance in third grade were observed in <strong>the</strong> current study, <strong>the</strong> results tell little<br />

about <strong>the</strong> external validity <strong>of</strong> <strong>the</strong>se <strong>influence</strong>s. To evaluate <strong>the</strong> validity <strong>of</strong> <strong>the</strong> current results<br />

we ran an additional regression analysis involving third grade ma<strong>the</strong>matics school grades as<br />

<strong>the</strong> dependent variable. Unfortunately, it was not possible to get <strong>the</strong> ma<strong>the</strong>matics grades from<br />

all children due to reasons <strong>of</strong> data protection. Never<strong>the</strong>less, we were able to collect <strong>the</strong><br />

ma<strong>the</strong>matics grades <strong>of</strong> a subsample <strong>of</strong> 54 children. A stepwise regression analysis was<br />

conducted predicting <strong>the</strong> ma<strong>the</strong>matics grade by <strong>the</strong> same predictors as incorporated in all<br />

o<strong>the</strong>r analyses with one exception. Due to <strong>the</strong> reduced sample we only differentiated between<br />

inversion related and inversion unrelated transcoding errors. <strong>The</strong> group <strong>of</strong> inversion related<br />

errors comprised all errors (including combination errors) that involved an error in digit order<br />

in at least one position, while all o<strong>the</strong>r errors were pooled in <strong>the</strong> category inversion unrelated<br />

errors. In line with our argument that <strong>place</strong>-<strong>value</strong> understanding may be a crucial building<br />

block for later arithmetic competencies it was observed that inversion related transcoding<br />

errors assessed in first grades were <strong>the</strong> only reliable predictor <strong>of</strong> ma<strong>the</strong>matics grade two years<br />

later (R = .50, adjusted R 2 = .22; F(2, 51) = 8.59, p < .001, f 2 = .33; b = .40, t = 3.15, p < .01)<br />

whereas inversion unrelated errors did not account for any additional variance (b = .15, t =<br />

1.13, p = .27). Based on this result we are confident that our tasks provide a reliable (see<br />

above) and valid estimate <strong>of</strong> children’s numerical competencies.<br />

<strong>The</strong> fact that <strong>the</strong> compatibility effect was not found to be a reliable predictor <strong>of</strong><br />

ma<strong>the</strong>matics grade (b = - .05, t = 0.38, p = .71) might be caused by <strong>the</strong> lower reliability <strong>of</strong> <strong>the</strong><br />

magnitude comparison task as compared to <strong>the</strong> transcoding task. <strong>The</strong> reliability <strong>of</strong> <strong>the</strong><br />

magnitude comparison task might be lower because it involved <strong>number</strong>s up to 100 and was<br />

thus ra<strong>the</strong>r difficult in general. In this context, it has to be noted that by <strong>the</strong> end <strong>of</strong> grade one<br />

(i.e., <strong>the</strong> time <strong>of</strong> assessing our participants) children in Austria are supposed to just master <strong>the</strong><br />

159

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!