<div dir="ltr"><div>Well, the issue is whether you want to err on the side of overestimating MLU (by excluding repetitions) or underestimating it (by including them). Part of the problem is that not all repetitions have the same status, or the same origin. Treating immediate repetitions differently from non-immediate repetitions is somewhat arbitrary. Non-immediate and immediate repetitions can both be a sign of perseveration, for example. Then, how do you want to treat perseverative utterances? If perseveration is a hallmark of the child's language, then what does it mean to calculate MLU excluding repetitions? Are we calculating an upper bound on the MLU instead of the actual average? Is this MLU reflective of child's competence or just artificial?<br>
</div><div>You either code your transcript in a way that differentiates repetitions that should not be counted (e.g. clarification repeats) from those that should be (e.g. perhaps perseveration) or... I don't know :-) Maybe one can calculate several MLUs with random exclusions of sentences and you can get a confidence interval for it. But this would be a poor substitute for making individual decisions about repeated utterances.<br>
</div><div>Note finally that repetitions are treated completely differently in the calculation of type-token ratios. In that measure, keeping repeats is crucial. Perseverative or repetitous language brings TTRs down... are we equally concerned?<br>
</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Fri, Jun 6, 2014 at 3:32 AM, Brian MacWhinney <span dir="ltr"><<a href="mailto:macw@cmu.edu" target="_blank">macw@cmu.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Dear Diane,<div> As noted by Natasha Rakhlin, repetitions are typically excluded from MLU. This is done automatically and by default in the CLAN MLU program, using the marking of repetitions with the <text> [/] and <text> [//] symbols. There is also a program called REPEAT that can add these marks if they are not present, but it is safer to do this carefully when transcribing. </div>
<div><br></div><div>— Brian MacWhinney</div><div><br></div><div><br></div><div>On Jun 5, 2014, at 6:04 PM, Diane Lillo-Martin <<a href="mailto:diane.lillomartin@gmail.com" target="_blank">diane.lillomartin@gmail.com</a>> wrote:<div>
<br><blockquote type="cite"><div dir="ltr">Dear all,<div>I would be very interested in knowing how you treat self-repetitions for various types of analyses, especially MLU.</div><div><br></div><div>In particular, I'm thinking of both single word and phrase repetitions, such as a sequence of repeating the word 'ball' while playing with the ball; or repetitions of phrases such as 'want cookie', either immediate or with some intervening talk.</div>
<div><br></div><div>I know that immediate repetitions are generally not counted according to the criteria established by Brown. I believe that they would be included in the CLAN calculation of MLU unless they are specifically tagged and the command is set to exclude them.</div>
<div><br></div><div>If you work with MLU or other measures for which it is relevant, how do you treat such repetitions?</div><div><br></div><div>Many thanks in advance,</div><div>Diane</div><div><br></div><div>----------</div>
<div>Diane Lillo-Martin</div><div>University of Connecticut</div><div><br></div></div><span class="HOEnZb"><font color="#888888"><div><br></div>
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