Rates

[Chris Fisher-2]

A small non-specific SPSS indulgence:

if i divide the total number of assaults in a system over a four month
period by the average daily population (per 100) during that 4 month
period  to calculate a rate...is that acceptable? Something in my head says
that may not be right, but I can't think of an authority to consult.

Your opinion/help is greatly appreciated.

Thank you.

--
Christopher Fisher, Ph.D.
Adjunct Professor
John Jay College of Criminal Justice
555 West 57th Street, Suite 605
New York, New York 10019
212-237-8000 (x2145)
212-237-8644 (fax)

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[Dubois, Marty A.]

 Chris,

If you're interested in calculating a "period" rate for these 4 months,
you would want to use the total population in your 4 month period as the
denominator. Or, if you're interested in an average daily rate for
assaults, you would want to use the average daily number of assaults as
the numerator for your rate calculation. IMHO.

Marty Du Bois, Research Analyst
Community Health Assessment Unit
Community Epidemiology Section
Community Health Services
Lake County Health Department and Community Health Center

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-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Chris Fisher
Sent: Wednesday, December 19, 2007 1:05 PM
To: [hidden email]
Subject: [SPSSX-L] Rates

A small non-specific SPSS indulgence:

if i divide the total number of assaults in a system over a four month
period by the average daily population (per 100) during that 4 month
period  to calculate a rate...is that acceptable? Something in my head
says that may not be right, but I can't think of an authority to
consult.

Your opinion/help is greatly appreciated.

Thank you.

--
Christopher Fisher, Ph.D.
Adjunct Professor
John Jay College of Criminal Justice
555 West 57th Street, Suite 605
New York, New York 10019
212-237-8000 (x2145)
212-237-8644 (fax)

=====================
To manage your subscription to SPSSX-L, send a message to
[hidden email] (not to SPSSX-L), with no body text except the
command. To leave the list, send the command SIGNOFF SPSSX-L For a list
of commands to manage subscriptions, send the command INFO REFCARD

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For a list of commands to manage subscriptions, send the command
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[bgreen]

>Chris,


Check out some recent papers to see what they use, or
http://www.aic.gov.au/. I recall suicide rates are often per 100,000.


Bob

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[David Greenberg]

Suppose that r is the rate, assumed to be constant over the four month period. To estimate r, in the numerator you will want the total number of assaults in the 4-month period.  if n_k is the population on the k-th day, the numerator will be rn_1 + r_n_2 + .... = r(n_1 + n_2 + ....). In the denominator you will want the total number of people who were at risk of committing an assault. That will be n_1 + n_2 + ..... , or the sum of the individual daily populations. If those populations are approximately constant over the four-month period, you will divide the total number of assaults by the product of that population and the number of days covered, to get the daily rate. David Greenberg, Sociology Department, New York University

----- Original Message -----
From: Chris Fisher <[hidden email]>
Date: Wednesday, December 19, 2007 3:01 pm
Subject: Rates
To: [hidden email]

> A small non-specific SPSS indulgence:
>
> if i divide the total number of assaults in a system over a four month
> period by the average daily population (per 100) during that 4 month
> period  to calculate a rate...is that acceptable? Something in my head
> says
> that may not be right, but I can't think of an authority to consult.
>
> Your opinion/help is greatly appreciated.
>
> Thank you.
>
> --
> Christopher Fisher, Ph.D.
> Adjunct Professor
> John Jay College of Criminal Justice
> 555 West 57th Street, Suite 605
> New York, New York 10019
> 212-237-8000 (x2145)
> 212-237-8644 (fax)
>
> =====================
> To manage your subscription to SPSSX-L, send a message to
> [hidden email] (not to SPSSX-L), with no body text except the
> command. To leave the list, send the command
> SIGNOFF SPSSX-L
> For a list of commands to manage subscriptions, send the command
> INFO REFCARD

=====================
To manage your subscription to SPSSX-L, send a message to
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