<div dir="ltr">Thanks for these references - really helpful discussion here. I'm going to use MATTR - simply because my samples are all quite small. Interestingly, I had CLAN compute voc-d first - and when I ran my statistical tests for any difference in vocd between the two datasets, there was a significant difference (a very small effect size). However, one dataset contained samples that were on average larger (i.e., more overall talk) than the other, and having read the references mentioned here I think the significant difference was likely spurious (because of the sensitivity of vocd to sample size - and small samples generally plus consistently (slightly) larger samples in the one dataset). I've had CLAN compute MATTR - the difference is not significant with this measure - and I feel more confident about its reliability for my small datasets.<br><br>Best wishes<br>Amber <br><br>On Thursday, 20 August 2015 14:31:03 UTC+1, Amanda Owen Van Horne wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr">Also see <div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px"><br></span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Owen, A. J., & Leonard, L. B. (2002). Lexical Diversity in the Spontaneous Speech of Children With Specific Language ImpairmentApplication of D.</span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Journal of Speech, Language, and Hearing Research</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">, </span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">45</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">(5), 927-937. </span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Bottom line is that VOCD is better than TTR, but less transparent. It does still vary with sample size, but to a lesser degree. </span></div><div><font face="Arial, sans-serif"><span style="line-height:16.1200008392334px"><br></span></font></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">McCarthy, P. M., & Jarvis, S. (2010). MTLD, vocd-D, and HD-D: A validation study of sophisticated approaches to lexical diversity assessment. </span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Behavior research methods</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">, </span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">42</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">(2), 381-392.</span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Compares various methods of computing D. Recommends a variety of measures. </span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px"><br></span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Koizumi, R. (2012). Relationships between text length and lexical diversity measures: can we use short texts of less than 100 tokens. </span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Vocabulary Learning and Instruction</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">, </span><i style="font-family:Arial,sans-serif;line-height:16.1200008392334px">1</i><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">(1), 60-69.</span><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px"><br></span></div><div><span style="font-family:Arial,sans-serif;line-height:16.1200008392334px">Recommends MLTD</span></div><div><font face="Arial, sans-serif"><span style="line-height:16.1200008392334px"><br></span></font></div><div><font face="Arial, sans-serif"><span style="line-height:16.1200008392334px"><br></span></font><br>On Wednesday, August 19, 2015 at 9:46:58 AM UTC-5, Amber wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">In fact, perhaps I should just post my question on here. The CHAT manual talks about calculating D and states that it can be done on samples as small as 50 tokens. However, reliability is less good for small samples. Could anyone advise me on whether VOCD is still a more valid measure than TTR, even for small transcripts (e.g., during a shared-book reading session)? I assume that as long as the sample is large enough for KIDEVAL to be able to give me VOCD values then it is OK?<br>Thanks<br>Amber<br><br>On Wednesday, 19 August 2015 15:36:05 UTC+1, Amber wrote:<blockquote class="gmail_quote" style="margin:0;margin-left:0.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear all<br><br>The CLAN manual contains the following link, which no longer appears to work. <br><br><a href="http://childes.psy.cmu.edu/manuals/vocd.doc" rel="nofollow" target="_blank" onmousedown="this.href='http://www.google.com/url?q\75http%3A%2F%2Fchildes.psy.cmu.edu%2Fmanuals%2Fvocd.doc\46sa\75D\46sntz\0751\46usg\75AFQjCNHi_xjQCNz2ip026UMrLfCH-xsnhQ';return true;" onclick="this.href='http://www.google.com/url?q\75http%3A%2F%2Fchildes.psy.cmu.edu%2Fmanuals%2Fvocd.doc\46sa\75D\46sntz\0751\46usg\75AFQjCNHi_xjQCNz2ip026UMrLfCH-xsnhQ';return true;">http://childes.psy.cmu.edu/<wbr>manuals/vocd.doc</a><br><br>Is there a new link to the VOCD manual/another similar article? <br><br>Many thanks<br>Amber<br><br></div></blockquote></div></blockquote></div></div></blockquote></div>
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