﻿ PISA

Here is another example of how the concept being tested is more important than the surface features of the question:

77% of the children marked 6 cm as the answer. The fact that most students selected the wrong response came as a surprise to the item developers who expected this to be an ‘easy question’. When asked the reason for selecting 6cm as the answer, students typically gave one of two explanations:

• The pencil ends at that point
• If we count off the markings from the starting point of the ruler to the pencil’s tip, we get 6.

Some students who chose the right answer (B: 5 cm) explained their choice by noting that if the pencil is shifted from its current position to the start of the ruler (i.e., 0), its tip will end at 5 cm, and hence the length of the pencil is 5 cm. Others, however, arrived at the correct response by counting off the ruler markings from the left end of the pencil to the right end, but “without counting the starting point” of the ruler. This suggests that even among the children getting the correct answer, the underlying concept is not completely clear.

Takeaways:

It appears that students are learning about measurement mainly by reading about it in textbooks and without much exposure to actually measuring things in real life. Most textbooks illustrate measurement by showing a line being measured starting from the zero mark. Thus, students seem to have learned the strategy – ‘look where the pencil ends to determine the answer’. Students in the above example did not understand that the length of the pencil could be obtained by calculating 6 cm -1 cm = 5 cm. This illustrates that exposure to concepts is more important than exposure to a rote solution. It also illustrates that children must be motivated to question and critically analyse everything that they observe. Rote learning hampers this kind of thinking