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<TITLE>RE: attrition in longitudinal studies</TITLE>
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<P><FONT SIZE=2>This is something I know a reasonable amount about, having worked on two longitudinal studies among possibly the lowest SES group possible - rural children in Tanzania, one of the poorest countries in the world. Both studies were looking at school aged children so, for this group, attrition may be slightly lower because parents are less likely to move the whole family if a child is in school. We found that some children stayed in the same school but their family care arrangements changed. In the second study we did however also look at children who were not in school and the dropout rate was higher. In that study it was 15-20% (over 2 years) and in the first study the figures (over 16 months) were as follows:</FONT></P>
<P><FONT SIZE=2>The total drop out rate was around 7% for educational achievement tests, 10% for tests of cognitive function and 15% for biometric measures. Dropouts were due to families moving away from the area (44% of all dropouts), dropping out of school (13%), withdrawal of parental consent (12%), chronic absenteeism (10%) and children refusing to participate (4%). </FONT></P>
<P><FONT SIZE=2>Strategies for following up are possibly a little different in this setting - no family has a telephone or a postal address and to find children's houses requires at least directions, if not accompaniment by another child or adult. We did have the advantage that in the first study (with 1000 children) all of them were in school at the start of the study and so we could send messages via their classmates if they did not attend school on the first day we were in their school for testing. This study took place in about 8 schools and the testing team was only in each school for a limited amount of time, and we had a very small window for repeat testing (about 2 weeks) so we may have been able to find more children if the window had been larger. Also, unless the child moved to another school in the study area, although we could have found more children as family and friends knew where they lived, and most moved a short distance, we could no longer include them in the study group due to the design of the study.</FONT></P>
<P><FONT SIZE=2> Unfortunately, for the second study, children who did not enrol in school by the age of 12 or so were even more likely to move away from the village. However, we had a less tight time window for testing, and so we were able to visit homes on repeated occasions. </FONT></P>
<P><FONT SIZE=2>Our main method of followup when sending messages via other children failed for both studies was sending a member of the team - either our dedicated coordination staff, who also planned testing timetables and gave children pre-testing snacks, or an interviewer who was planning to interview a parent - to the child's home. This was often a sensitive matter as parents had fears about the study, taking blood samples etc. This was obviously time-consuming but we did find that direct contact with the parents helped a lot, as well as holding school and village meetings before each followup period.</FONT></P>
<P><FONT SIZE=2>On a slightly more down-to-earth note - I know that the TEDS study asks parents for the address and phone number of someone (e.g. a grandparent or friend) who is not likely to move during the period of the study, as an additional contact avenue. Another group employs an ex-social-worker as their followup liason person.</FONT></P>
<P><FONT SIZE=2>Katie Alcock</FONT>
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<P><FONT SIZE=2>Katie Alcock, DPhil</FONT>
<BR><FONT SIZE=2>Lecturer</FONT>
<BR><FONT SIZE=2>Department of Psychology</FONT>
<BR><FONT SIZE=2>City University</FONT>
<BR><FONT SIZE=2>Northampton Square</FONT>
<BR><FONT SIZE=2>London EC1V 0HB</FONT>
<BR><FONT SIZE=2>Phone (+44) (0)20 7040 0167</FONT>
<BR><FONT SIZE=2>Fax (+44) (0)20 7040 8581</FONT>
<BR><FONT SIZE=2>Web <A HREF="http://www.staff.city.ac.uk/k.j.alcock" TARGET="_blank">http://www.staff.city.ac.uk/k.j.alcock</A></FONT>
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<P><FONT SIZE=2>> -----Original Message-----</FONT>
<BR><FONT SIZE=2>> From: Shelley Velleman [<A HREF="mailto:velleman@comdis.umass.edu">mailto:velleman@comdis.umass.edu</A>]</FONT>
<BR><FONT SIZE=2>> Sent: 12 June 2003 01:15</FONT>
<BR><FONT SIZE=2>> To: info-childes@mail.talkbank.org</FONT>
<BR><FONT SIZE=2>> Subject: attrition in longitudinal studies</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Assistance urgently needed!</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> I need to know what kinds of attrition rates people have had</FONT>
<BR><FONT SIZE=2>> in longitudinal studies, especially of very young kids (I hope to be</FONT>
<BR><FONT SIZE=2>> following mine from 12 - 42 months). Especially if you've </FONT>
<BR><FONT SIZE=2>> had experience</FONT>
<BR><FONT SIZE=2>> with low SES groups, I'd really appreciate you sharing your </FONT>
<BR><FONT SIZE=2>> experience,</FONT>
<BR><FONT SIZE=2>> including any strategies that helped to reduce attrition.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Please include:</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Age range:</FONT>
<BR><FONT SIZE=2>> SES: </FONT>
<BR><FONT SIZE=2>> Strategies that did or did not work to reduce attrition (Please state</FONT>
<BR><FONT SIZE=2>> which!):</FONT>
<BR><FONT SIZE=2>> Location:</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Many thanks!!</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Shelley Velleman</FONT>
<BR><FONT SIZE=2>> UMass - Amherst</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
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