Having worked at several bibliographic database companies, I can assure
you, this is A Thing. It's not huge, but it's enough to be quite
noticeable. Publishers re-use ISBNs, and it drives data recipients crazy.

On 5/20/13 2:02 PM, "Shlomo Sanders" <[log in to unmask]>
wrote:

>Sorry, no numbers, but I have heard complaints of different works having
>the same ISBN.
>
>Thanks,
>Shlomo
>
>Sent from my iPad
>
>On May 20, 2013, at 20:53, "Harold E. Thiele" <[log in to unmask]>
>wrote:
>
>> Thanks to Mac and Roy, we now have some hard numbers revealing the
>>number of records having no association with ISBN numbers or are
>>associated with multiple ISBN numbers. This is just one side of the
>>problem. The other side, mentioned several times, is the association of
>>a single ISBN number with two or more works or instances. It would be
>>equally informative if the numbers could be generated to illustrate the
>>size of this problem.
>>
>>
>> Harold E. Thiele, MLIS, PhD
>> Assistant Professor
>> Master of Library and Information Science Program
>> Odum Library
>> Valdosta State University
>> 1500 N. Patterson St.
>> Valdosta, GA 31698-0150
>> email - [log in to unmask]
>> voice: 229 333 5966 fax 229 259 5055
>>
>> ________________________________________
>> From: Bibliographic Framework Transition Initiative Forum
>>[[log in to unmask]] on behalf of Tennant,Roy [[log in to unmask]]
>> Sent: Monday, May 20, 2013 11:06 AM
>> To: [log in to unmask]
>> Subject: Re: [BIBFRAME] Instance of ISBNs in MARC records
>>
>> As requested, numbers from WorldCat, the 1 May 2013 Research snapshot,
>>with 296,589,450 records:
>>
>> NO. of Recs ISBNs Percent
>>
>> 230402772 0 77.68%
>> 58861390 2 19.85%
>> 4269211 4 1.44%
>> 1659221 1 0.56%
>> 515674 6 0.17%
>> 466645 3 0.16%
>> 151133 8 0.05%
>> 84572 5 0.03%
>> 51967 10 0.02%
>> 33372 12 0.01%
>>
>> Keep in mind that WorldCat, being the largest library union database in
>>the world, includes a great deal of material that pre-dates the
>>establishment of the ISBN.
>> Roy
>>
>> From: Shlomo Sanders
>><[log in to unmask]<mailto:[log in to unmask]
>>>>
>> Reply-To: Bibliographic Framework Transition Initiative Forum
>><[log in to unmask]<mailto:[log in to unmask]>>
>> Date: Monday, May 20, 2013 5/20/13 € 6:19 AM
>> To: "[log in to unmask]<mailto:[log in to unmask]>"
>><[log in to unmask]<mailto:[log in to unmask]>>
>> Subject: Re: [BIBFRAME] Instance of ISBNs in MARC records
>>
>> From a large sample of data that we get from publishers:
>>
>> * Only 24.5% with one ISBN!
>> * 40% with multiple ISBNs!
>> * Largest group has no ISBN!
>>
>>
>> ISBN Count Percentage of records with X ISBNs
>> 0 38.57%
>> 1 24.49%
>> 2 17.00%
>> 3 5.88%
>> 4 10.77%
>> 5 2.14%
>> 6 0.65%
>> 7 0.09%
>> 8 0.12%
>> 9 0.24%
>> 10 0.04%
>>
>>
>> Thanks,
>> Shlomo
>>
>> Experience the all-new, singing and dancing interactive Primo brochure
>>
>>
>> -----Original Message-----
>> From: Bibliographic Framework Transition Initiative Forum
>>[mailto:[log in to unmask]] On Behalf Of J. McRee Elrod
>> Sent: Sunday, May 19, 2013 20:34
>> To: [log in to unmask]<mailto:[log in to unmask]>
>> Subject: Re: [BIBFRAME] Instance of ISBNs in MARC records
>>
>> In SLC's database of over 300,000 records, over 169,000 have no ISBN,
>>over 114,000 have one, over 19,000 have two, and the number of ISBNs
>>ranges up to 36 in one record.
>>
>> For us, Instances can't be based on ISBNs.
>>
>>
>> Total Records: 315389
>>
>> 020s Records
>>
>> 00 169021
>> 01 114221
>> 02 19745
>> 03 7403
>> 04 3238
>> 05 1149
>> 06 344
>> 07 118
>> 08 29
>> 09 42
>> 10 11
>> 11 16
>> 12 10
>> 13 12
>> 14 4
>> 15 5
>> 16 3
>> 17 7
>> 18 1
>> 19 1
>> 21 1
>> 22 1
>> 23 1
>> 25 3
>> 27 1
>> 28 1
>> 36 1
>>
>>
>>
>> __ __ J. McRee (Mac) Elrod
>>([log in to unmask]<mailto:[log in to unmask]>)
>> {__ | / Special Libraries Cataloguing HTTP://www.slc.bc.ca/
>> ___} |__ \__________________________________________________________
>>