What does implication mean? An exploration of undergraduates’ vocabulary size and academic achievement

The aim of this research was to explore undergraduates’ receptive knowledge of vocabulary and how these relate to academic achievement to improve educational outcomes for students. An estimate of UG students’ receptive vocabulary knowledge was measured by administering a vocabulary size test devised by Goulden et al (1990) to 389 undergraduates in one HE institution. These were tested for correlations between vocabulary knowledge and academic achievement measured using expected degree classifications.


Key findings suggest that undergraduates have a much smaller vocabulary size than one would expect compared to previous research (e.g. Hartmann, 1946; Nusbaum et al, 1984; Goulden et al, 1990; D’Anna et al, 1991; Anderson and Nagy, 1993; Zechmeister et al, 1995) but not compared to findings from Treffers-Daller and Milton (2013).

Study Estimate Sample
Hartmann (1946) 215,000 US undergraduates
Anderson and Nagy (1993) 40,000 US high school seniors
Goulden et al (1990) 17,200 US undergraduates
D’Anna et al (1991) 17,000 US undergraduates
Nusbaum et al (1984) 14,400 US undergraduates
Zechmeister et al (1995) 12,000 US undergraduates
Treffers-Daller and Milton (2013) 9,800 UK first year undergraduates
Current study 11,088 UK undergraduates

There are statistically significant differences in the mean vocabulary size of students between Stage 1 (10,070) and Stage 2  (11,614). However, the effect size (r) = 0.26 indicates this difference is small suggesting that students’ vocabulary sizes change between Stages 1 and 2 but not to a substantial extent. It was hypothesised that vocabulary sizes would play a role in academic achievement. In other words, a larger vocabulary size would link to a higher degree classification. However, there is no difference between the mean vocabulary size of students predicted a first (11,521) and those who were predicted a 2:1  (11,312); 2:2 (11,450) and a 3rd  (9,833).

What does this mean for both practitioners and students?

1) UG students experience changes in their vocabulary sizes between the first and second stage of study but plateau in their final year. This plateau might indicate poor reading skills which can negatively affect vocabulary sizes (Nation & Coxhead, 2021). The importance of reading in HE cannot be understated (Leamnson, 1999; Bharuthram, 2012; Colombo & Prior, 2016; Gunobgunob-Mirasol, 2019) and measures to help students improve their reading skills could be actioned.

2) The findings contribute to the growing consensus around the number of English words native speakers know (Nation & Coxhead, 2020). They can also provide a learning goal for learners of English wishing to attend HE institutions in the UK. However, minimum scores for each stage were 5,500, 5,000 and 4,000 meaning some native English-speaking students are at the minimum threshold for L2 learners (Laufer & Ravenhorst-Kalovski, 2010). This suggests some native speakers may need some language support to close this vocabulary gap.

3) Factors other than vocabulary size and academic word usage may play a greater role in student achievement.