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Index of Subjects --Apple-Mail-728B7079-62C0-4428-B9DC-FC0B10C8DF58 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable I used to use a lot of x's in my ebird submissions until someone told me tha= t scientists behind ebird actually preferred estimates since count data can a= lways be converted to presence/absence but the opposite is not true.=20 Ebird has some good reference material under the help section that provides t= he logic behind preferring estimates over x's. Here is a link:=20 http://help.ebird.org/customer/portal/articles/1006732-the-trouble-with-x---= why-you-should-always-estimate-numbers- Ebird also has a two part tutorial on how to count and/or estimate numbers o= f birds in large flocks. I found these articles to be very helpful.=20 http://ebird.org/plone/ebird/news/bird-counting-101 http://ebird.org/plone/ebird/news/bird-counting-201 Cheers, Graham Williams Longwood, Fl Sent from my iPhone On Jul 9, 2013, at 9:32 AM, Nancy P Dowd <nancypdowd@gmail.com> wrote: > You have convinced me to submit my sightings as numbers on eBird. Now I wi= ll have to persuade my brother (a statistics prof himself) of this.=20 >=20 > He still feels that presence/absence (x or blank) is the only reliable rep= ort for these bird surveys. Despite the limited statistical analysis that ca= n be done on such data.=20 >=20 > Nancy >=20 > Sent from my iPhone >=20 > On 2013-07-08, at 12:12 PM, iamclar@dal.ca wrote: >=20 >> All: >>=20 >> Nancy's dilemma and suggestions on estimating numbers for eBird are impor= tant. I have been a frequent user of eBird, atlas, CBC, BBS, etc., over the y= ears in estimating trends and patterns,. I believe the dictum of a statistic= ian colleague that "a large number of bad numbers (as long as not biassed) a= re as good as a small number of good numbers" (a recasting of the "law of la= rge numbers"). Even the casual reporting of numbers like "lots" or "common" o= n naturens are less useful for section editors of "NS Birds" than are estima= tes. >>=20 >> Nancy suggests that a range of categories could be available on eBird 2-1= 0, 11-50, etc., but the "users" of these numbers would still have to turn th= ese into a single number for trend analyses, etc. I believe that an educated= guess is better; Why not just take the rough number between 11 and 50, e,g.= , that you think might be better - 20 or 40? >>=20 >> Another possible guide might be that used during the first (1980s) NS Atl= assers of entering log categories 1-10, 10-100, etc. (natural logs even bett= er). Then (as was done) the user (or indeed the observer) can use the geomet= ric mean (about 3, about 30, etc.). >>=20 >> Cheers, Ian >>=20 >> Ian McLaren >>=20 --Apple-Mail-728B7079-62C0-4428-B9DC-FC0B10C8DF58 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable <html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D= utf-8"></head><body dir=3D"auto"><div style=3D"-webkit-text-size-adjust: aut= o; ">I used to use a lot of x's in my ebird submissions until someone told m= e that scientists behind ebird actually preferred estimates since count data= can always be converted to presence/absence but the opposite is not true.&n= bsp;</div><div style=3D"-webkit-text-size-adjust: auto; "><br></div><div sty= le=3D"-webkit-text-size-adjust: auto; ">Ebird has some good reference materi= al under the help section that provides the logic behind preferring estimate= s over x's. Here is a link: </div><div style=3D"-webkit-text-size-adjus= t: auto; "><br></div><div><a href=3D"http://help.ebird.org/customer/portal/a= rticles/1006732-the-trouble-with-x---why-you-should-always-estimate-numbers-= ">http://help.ebird.org/customer/portal/articles/1006732-the-trouble-with-x-= --why-you-should-always-estimate-numbers-</a><font face=3D".HelveticaNeueUI"= ><span style=3D"font-size: 15px; line-height: 19px; white-space: nowrap; -we= bkit-tap-highlight-color: rgba(26, 26, 26, 0.292969); -webkit-composition-fi= ll-color: rgba(175, 192, 227, 0.230469); -webkit-composition-frame-color: rg= ba(77, 128, 180, 0.230469);"><br></span></font><br>Ebird also has a two part= tutorial on how to count and/or estimate numbers of birds in large flocks. I= found these articles to be very helpful. </div><div><br></div><div><a h= ref=3D"http://ebird.org/plone/ebird/news/bird-counting-101">http://ebird.org= /plone/ebird/news/bird-counting-101</a></div><div><br></div><div><a href=3D"= http://ebird.org/plone/ebird/news/bird-counting-201">http://ebird.org/plone/= ebird/news/bird-counting-201</a></div><div><br></div><div>Cheers,</div><div>= Graham Williams</div><div>Longwood, Fl</div><div><br><br><span style=3D"-web= kit-text-size-adjust: auto;">Sent from my iPhone</span></div><div style=3D"-= webkit-text-size-adjust: auto; "><br>On Jul 9, 2013, at 9:32 AM, Nancy P Dow= d <nancypdowd@gmail.com> w= rote:<br><br></div><blockquote type=3D"cite" style=3D"-webkit-text-size-adju= st: auto; "><div><span>You have convinced me to submit my sightings as numbe= rs on eBird. Now I will have to persuade my brother (a statistics prof himse= lf) of this. </span><br><span></span><br><span>He still feels that presence/= absence (x or blank) is the only reliable report for these bird surveys. Des= pite the limited statistical analysis that can be done on such data. </span>= <br><span></span><br><span>Nancy</span><br><span></span><br><span>Sent from m= y iPhone</span><br><span></span><br><span>On 2013-07-08, at 12:12 PM, <a hre= f=3D"mailto:iamclar@dal.ca">iamclar@dal.ca</a> wrote:</span><br><span></span= ><br><blockquote type=3D"cite"><span>All:</span><br></blockquote><blockquote= type=3D"cite"><span></span><br></blockquote><blockquote type=3D"cite"><span= >Nancy's dilemma and suggestions on estimating numbers for eBird are importa= nt. I have been a frequent user of eBird, atlas, CBC, BBS, etc., over the ye= ars in estimating trends and patterns,. I believe the dictum of a statistici= an colleague that "a large number of bad numbers (as long as not biassed) ar= e as good as a small number of good numbers" (a recasting of the "law of lar= ge numbers"). Even the casual reporting of numbers like "lots" or "common" o= n naturens are less useful for section editors of "NS Birds" than are estima= tes.</span><br></blockquote><blockquote type=3D"cite"><span></span><br></blo= ckquote><blockquote type=3D"cite"><span>Nancy suggests that a range of categ= ories could be available on eBird 2-10, 11-50, etc., but the "users" of thes= e numbers would still have to turn these into a single number for trend anal= yses, etc. I believe that an educated guess is better; Why not just take the= rough number between 11 and 50, e,g., that you think might be better - 20 o= r 40?</span><br></blockquote><blockquote type=3D"cite"><span></span><br></bl= ockquote><blockquote type=3D"cite"><span>Another possible guide might be tha= t used during the first (1980s) NS Atlassers of entering log categories 1-10= , 10-100, etc. (natural logs even better). Then (as was done) the user (or i= ndeed the observer) can use the geometric mean (about 3, about 30, etc.).</s= pan><br></blockquote><blockquote type=3D"cite"><span></span><br></blockquote= ><blockquote type=3D"cite"><span>Cheers, Ian</span><br></blockquote><blockqu= ote type=3D"cite"><span></span><br></blockquote><blockquote type=3D"cite"><s= pan>Ian McLaren</span><br></blockquote><blockquote type=3D"cite"><span></spa= n><br></blockquote></div></blockquote></body></html>= --Apple-Mail-728B7079-62C0-4428-B9DC-FC0B10C8DF58--
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