New subject: Rounding and Totalling in CTPP Part 1 Data

28 Jul 2003

Peter,
All numbers in CTPP are rounded.  The rounding rules are as follows:
Any number from 0-7 is rounded to 4.
Any other number is rounded to the nearest 5.

Totals in tables are rounded independently of the cells, so cell values may not add up to
the total.

SF 3, being a standard product of the decennial census, did not have any rounding.
Nandu

-----Original Message-----
From: peter(a)caliper.com 
Sent: Monday, July 28, 2003 12:59 PM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] Rounding and Totalling in CTPP Part 1 Data

All:

Has anyone else noticed that the values for counts in the CTPP Part 1 data 
always seem to be rounded to multiples of 5 (except for 5 itself, which 
usually seems to be 4)?

Also, it seems that the total for a variable rarely is the sum of the other 
values for that variable. For example:

- If you add up the individual means of transportation, only coincidentally 
will they add up to the total of all means of transportation, using the 
Both Sexes fields in Table 1-002

- When you look at the same data in SF 3, the values are close but 
different, clearly not rounded to multiples of 5 and definitely adding up 
to the expected total (in this case, All Workers)

Peter

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Peter Van Demark
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Caliper Corporation                            Fax: 617-527-5113
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RE: [CTPP] Rounding and Totalling in CTPP Part 1 Data