Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Dr. Snow, thanks so much for your response to my question.

I think I'm going to stick with the lower- and upper-bounds method I
described, even though it gives a wider range for the median age than
other methods. I read the vignette for 'survival' as well at the
chapters on survival from MASS and another book I have, and couldn't
make heads or tails of it, much less how to apply it to this question.
In the unlikely event of someone asking me to explain or defend my
conclusions on median age for my neighborhood population, I would be
lost about survival statistics, but could manage, with numerous hand-
waves, to explain my method. I'm an old, retired guy who thinks
statistics are fun, not someone with any kind of professional training
or credentials.

Thank you, again, for your thoughtful and thorough response. I
appreciate your help.

-Kevin

On Tue, 2023-09-05 at 11:31 -0600, Greg Snow wrote:
> Kevin,
> 
> Your idea of substituting the minimum and maximum values of the
> ranges
> will work for computing bounds on the median age, and for the median
> age you should not need to drop the 85+ group (unless more that 50%
> of
> people are in that group).  The mean is another issue.
> 
> Another approach that may give you a smaller interval and more
> statistically justified range would be to turn to survival analysis
> techniques and treat the values from the table as interval censored
> data.  If the data appears to come from a known distribution then you
> can use parametric survival techniques to fit the distribution (see
> the `survreg` function in the `survival` package).  Or, there are
> packages that fit non-parametric models to interval censored data
> (`Icens` and `interval` for example) that can then be used to
> estimate
> a confidence interval on the median age (and possibly the mean age,
> but with limitations).  For the 85+ group you can treat them as right
> censored, or interval censored from 85 to infinity, or interval
> censored from 85 to some value like 100 or 120 (there is a small
> chance that someone in the table could be over 100, but rare, I think
> the current oldest reported living person is in the hundred and
> teens,
> so 120 would be safe).
> 
> On Thu, Aug 31, 2023 at 1:48 PM Kevin Zembower via R-sig-Geo
>  wrote:
> > 
> > Sorry to resurrect a long-dead thread, but I'm still struggling
> > with my
> > desire to assign a median age to the population in a group of US
> > census
> > blocks. I'm using the data from the US Census table P12, which bins
> > the
> > ages into ranges.
> > 
> > I'm convinced (thank you!) that I can't compute the exact median
> > age.
> > Can I compute the lower and upper bounds of the median age? Can I
> > assign all the people in a binned age range (say "20 to 29 years")
> > to
> > the lower limit of the range, then compute the median of those
> > ages,
> > and say that the true median age is between this lower limit and
> > the
> > upper one, computed similarly?
> > 
> > If this is valid, how do I deal with the "85 years and older" bin?
> > I
> > have 9 people 85 years and older, out of a total population of 537
> > people in my group of census blocks. For the lower bounds of the
> > median, I assign all 9 the age of 85. What can I do for the upper
> > bounds?
> > 
> > I've done this, and found that the true median age is between 40
> > and 44
> > years old, if I drop all the "85 years and older" population as NA.
> > The
> > true mean is between 39.96 and 43.46, similarly.
> > 
> > One thought: If there are 9 people in the "85 years and older"
> > group,
> > should I drop them and also drop the 9 youngest ages?
> > 
> > I look forward to reading your thoughts. Thank you for any advice
> > and
> > guidance.
> > 
> > -Kevin
> > 
> > On Tue, 2023-08-08 at 12:00 +0200, r-sig-geo-requ...@r-project.org
> > wrote:
> > > 
> > > Message: 2
> > > Date: Mon, 7 Aug 2023 18:33:41 +
> > > From: Kevin Zembower 
> > > To: "r-sig-geo@r-project.org" 
> > > Subject: [R-sig-Geo] Calculating median age for a group of US
> > > census
> > >     blocks?
> > > Message-ID:
> > >     <01000189d146bd0d-ecb41aac-0501-46f4-b313-a1faebeff2a9-
> > > 000...@email.amazonses.com>
> > > 
> > > Content-Type: text/plain; charset="utf-8"
> > > 
> > > Hello, all,
> > > 
> > > I'd like to obtain the median age for a population in a specific
> > > group
> > > of US Decennial census blocks. 

[R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Sorry to resurrect a long-dead thread, but I'm still struggling with my
desire to assign a median age to the population in a group of US census
blocks. I'm using the data from the US Census table P12, which bins the
ages into ranges.

I'm convinced (thank you!) that I can't compute the exact median age.
Can I compute the lower and upper bounds of the median age? Can I
assign all the people in a binned age range (say "20 to 29 years") to
the lower limit of the range, then compute the median of those ages,
and say that the true median age is between this lower limit and the
upper one, computed similarly?

If this is valid, how do I deal with the "85 years and older" bin? I
have 9 people 85 years and older, out of a total population of 537
people in my group of census blocks. For the lower bounds of the
median, I assign all 9 the age of 85. What can I do for the upper
bounds? 

I've done this, and found that the true median age is between 40 and 44
years old, if I drop all the "85 years and older" population as NA. The
true mean is between 39.96 and 43.46, similarly. 

One thought: If there are 9 people in the "85 years and older" group,
should I drop them and also drop the 9 youngest ages?

I look forward to reading your thoughts. Thank you for any advice and
guidance.

-Kevin

On Tue, 2023-08-08 at 12:00 +0200, r-sig-geo-requ...@r-project.org
wrote:
> 
> Message: 2
> Date: Mon, 7 Aug 2023 18:33:41 +
> From: Kevin Zembower 
> To: "r-sig-geo@r-project.org" 
> Subject: [R-sig-Geo] Calculating median age for a group of US census
> blocks?
> Message-ID:
> <01000189d146bd0d-ecb41aac-0501-46f4-b313-a1faebeff2a9-
> 000...@email.amazonses.com>
> 
> Content-Type: text/plain; charset="utf-8"
> 
> Hello, all,
> 
> I'd like to obtain the median age for a population in a specific
> group 
> of US Decennial census blocks. Here's an example of the problem:
> 
> ## Example of calculating median age of population in census blocks.
> library(tidyverse)
> library(tidycensus)
> 
> counts <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P1",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
>     substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>     )
> 
> ages <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P13",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
>     substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>     )
> 
> I have two questions:
> 
> 1. Is it mathematically valid to multiply the population of a block
> by 
> the median age of that block (in other words, assign the median age
> to 
> each member of a block), then calculate the median of those numbers
> for 
> a group of blocks?
> 
> 2. Is raw data on the ages of individuals available anywhere else in
> the 
> census data? I can find tables such as P12, that breaks down the 
> population by age ranges or bins, but can't find specific data of
> counts 
> per age in years.
> 
> Thanks for your advice and help.
> 
> -Kevin
> 
> 
> 
> 
> --
> 
> Message: 3
> Date: Mon, 7 Aug 2023 14:38:16 -0400
> From: Josiah Parry 
> To: Kevin Zembower 
> Cc: "r-sig-geo@r-project.org" 
> Subject: Re: [R-sig-Geo]  Calculating median age for a group of US
> census blocks?
> Message-ID:
> <
> cal3ufujvvczvdtym2v0tmo9u-rmz1zogl8nzdhjk7v8gfc7...@mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hey Kevin, I don't think you're going to be able to get individual
> level
> data from the US Census Bureau. The closest you may be able to get is
> the
> current population survey (CPS) which I believe is also available via
> tidycensus. Regarding your first question, I'm not sure I follow what
> your
> objective is with it. I would use a geography of census block groups
> as the
> measure of median for census block groups. Otherwise it is unclear
> how you
> are defining what a "group of blocks" is.
> 
> --
> 
> Message: 4
> Date: Mon, 7 Aug 2023 19:00:38 +
> From: Kevin Zembower 
> To: Josiah Parry 
> Cc: "r-sig-geo@r-project.org" 
> Subject: Re: [R-sig-Geo]  Calculating median age for a

Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Dexter, Thanks so much for your reply. I wasn't aware of the two sources 
you cite, and I'll be sure to include them in my work.

The open Baltimore website, at 
https://data.baltimorecity.gov/datasets/neighborhood-1/explore, has 
statistics for my neighborhood, Radnor-Winston 
(https://radnorwinston.org).The Baltimore Neighborhood Indicators 
Alliance at https://bniajfi.org/vital_signs/ lumps us into North 
Baltimore/Guilford/Homeland, which, as I'm sure you're aware, contains 
many homes (mansions!) with very different characteristics than the 
people of Radnor-Winston.

Thanks, again, for your help and expertise. I learned a lot from your note.

-Kevin

On 8/7/23 15:43, Dexter Locke wrote:
> Hi Kevin and all,
> 
> Given the binned data, you could count the number of people per age 
> class for those 10 blocks. You can then express that in a number of 
> different ways, like percent under 25 years old, or by calculating the 
> dependency ratio 
> .
> 
> I do think it is feasible to calculate an estimated mean from the counts 
> within groups representing ranges. See, for example, here: 
> https://stackoverflow.com/questions/18887382/how-to-calculate-the-median-on-grouped-dataset
>  
> 
> 
> Since you are working in Baltimore, you may consider looking at The 
> Baltimore Neighborhood Indicators Alliance 
> https://bniajfi.org/vital_signs/ . 
> They provide useful data on a range of issues (transportation, crime, 
> education, environment etc.) including summaries from Census-derived 
> demographics. What you are seeking may already exist. BNIA creates 
> neighborhoods or "community statistical areas" (n=55) based on 
> aggregates of Census data.
> 
> Although not pertaining to age, Baltimore City Planning has paid Census 
> in the past to aggregate from individual-level Census data to the more 
> colloquially-used definitions of Baltimore shown here (n = 273): 
> https://data.baltimorecity.gov/datasets/neighborhood-1/explore?location=39.284832%2C-76.620516%2C12.91
>  
> 
> 
> Best, Dexter
> https://dexterlocke.com/ 
> 
> 
> 
> 
> 
> On Mon, Aug 7, 2023 at 3:02 PM Kevin Zembower via R-sig-Geo 
> mailto:r-sig-geo@r-project.org>> wrote:
> 
> Josiah, thanks for your reply.
> 
> Regarding my objective, I'm trying to compile census statistics for the
> blocks that make up the neighborhood where I live. It consists of ten
> census blocks, of which I selected three for simplicity in my example.
> The census block-group which contains these ten blocks also contains
> some blocks which are outside of my neighborhood and shouldn't be
> counted or included.
> 
> Since I won't be able to calculate the median age from the age and
> count
> data, and since the individual data doesn't seem to be available, is it
> your thought that I can't produce a valid median age for a group of
> census blocks?
> 
> Thanks so much for your advice.
> 
> -Kevin
> 
> On 8/7/23 14:38, Josiah Parry wrote:
>  > Hey Kevin, I don't think you're going to be able to get
> individual level
>  > data from the US Census Bureau. The closest you may be able to
> get is
>  > the current population survey (CPS) which I believe is also
> available
>  > via tidycensus. Regarding your first question, I'm not sure I follow
>  > what your objective is with it. I would use a geography of census
> block
>  > groups as the measure of median for census block groups.
> Otherwise it is
>  > unclear how you are defining what a "group of blocks" is.
>  >
>  > On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo
>  > mailto:r-sig-geo@r-project.org>
> >>
> wrote:
>  >
>  >     Hello, all,
>  >
>  >     I'd like to obtain the median age for a population in a
> specific group
>  >     of US Decennial census blocks. Here's an example of the problem:
>  >
>  >     ## Example of calculating median age of population in census
> blocks.
>  >     library(tidyverse)
>  >     library(tidycensus)
>  >
>  >     counts <- get_decennial(
>  >           geography = "block",
>  >           state = "MD",
>  >           county = "Baltimore city",
>  >           table = "P1",
>  >           year = 2020,
>  >           sumfile = "dhc") %>%
>  >           mutate(NAME = NULL) %>%
>  >           filter(substr(GEOID, 6, 11) == "271101" &
>  >                  substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>  >            

Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Dexter Locke]

Hi Kevin and all,

Given the binned data, you could count the number of people per age class
for those 10 blocks. You can then express that in a number of
different ways, like percent under 25 years old, or by calculating the
dependency
ratio

.

I do think it is feasible to calculate an estimated mean from the counts
within groups representing ranges. See, for example, here:
https://stackoverflow.com/questions/18887382/how-to-calculate-the-median-on-grouped-dataset

Since you are working in Baltimore, you may consider looking at The
Baltimore Neighborhood Indicators Alliance https://bniajfi.org/vital_signs/.
They provide useful data on a range of issues (transportation, crime,
education, environment etc.) including summaries from Census-derived
demographics. What you are seeking may already exist. BNIA creates
neighborhoods or "community statistical areas" (n=55) based on aggregates
of Census data.

Although not pertaining to age, Baltimore City Planning has paid Census in
the past to aggregate from individual-level Census data to the more
colloquially-used definitions of Baltimore shown here (n = 273):
https://data.baltimorecity.gov/datasets/neighborhood-1/explore?location=39.284832%2C-76.620516%2C12.91

Best, Dexter
https://dexterlocke.com/





On Mon, Aug 7, 2023 at 3:02 PM Kevin Zembower via R-sig-Geo <
r-sig-geo@r-project.org> wrote:

> Josiah, thanks for your reply.
>
> Regarding my objective, I'm trying to compile census statistics for the
> blocks that make up the neighborhood where I live. It consists of ten
> census blocks, of which I selected three for simplicity in my example.
> The census block-group which contains these ten blocks also contains
> some blocks which are outside of my neighborhood and shouldn't be
> counted or included.
>
> Since I won't be able to calculate the median age from the age and count
> data, and since the individual data doesn't seem to be available, is it
> your thought that I can't produce a valid median age for a group of
> census blocks?
>
> Thanks so much for your advice.
>
> -Kevin
>
> On 8/7/23 14:38, Josiah Parry wrote:
> > Hey Kevin, I don't think you're going to be able to get individual level
> > data from the US Census Bureau. The closest you may be able to get is
> > the current population survey (CPS) which I believe is also available
> > via tidycensus. Regarding your first question, I'm not sure I follow
> > what your objective is with it. I would use a geography of census block
> > groups as the measure of median for census block groups. Otherwise it is
> > unclear how you are defining what a "group of blocks" is.
> >
> > On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo
> > mailto:r-sig-geo@r-project.org>> wrote:
> >
> > Hello, all,
> >
> > I'd like to obtain the median age for a population in a specific
> group
> > of US Decennial census blocks. Here's an example of the problem:
> >
> > ## Example of calculating median age of population in census blocks.
> > library(tidyverse)
> > library(tidycensus)
> >
> > counts <- get_decennial(
> >   geography = "block",
> >   state = "MD",
> >   county = "Baltimore city",
> >   table = "P1",
> >   year = 2020,
> >   sumfile = "dhc") %>%
> >   mutate(NAME = NULL) %>%
> >   filter(substr(GEOID, 6, 11) == "271101" &
> >  substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> >  )
> >
> > ages <- get_decennial(
> >   geography = "block",
> >   state = "MD",
> >   county = "Baltimore city",
> >   table = "P13",
> >   year = 2020,
> >   sumfile = "dhc") %>%
> >   mutate(NAME = NULL) %>%
> >   filter(substr(GEOID, 6, 11) == "271101" &
> >  substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> >  )
> >
> > I have two questions:
> >
> > 1. Is it mathematically valid to multiply the population of a block
> by
> > the median age of that block (in other words, assign the median age
> to
> > each member of a block), then calculate the median of those numbers
> for
> > a group of blocks?
> >
> > 2. Is raw data on the ages of individuals available anywhere else in
> > the
> > census data? I can find tables such as P12, that breaks down the
> > population by age ranges or bins, but can't find specific data of
> > counts
> > per age in years.
> >
> > Thanks for your advice and help.
> >
> > -Kevin
> >
> > ___
> > R-sig-Geo mailing list
> > R-sig-Geo@r-project.org 
> > https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> > 
> >
>
>
> ___
> 

Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Josiah, thanks for your reply.

Regarding my objective, I'm trying to compile census statistics for the 
blocks that make up the neighborhood where I live. It consists of ten 
census blocks, of which I selected three for simplicity in my example. 
The census block-group which contains these ten blocks also contains 
some blocks which are outside of my neighborhood and shouldn't be 
counted or included.

Since I won't be able to calculate the median age from the age and count 
data, and since the individual data doesn't seem to be available, is it 
your thought that I can't produce a valid median age for a group of 
census blocks?

Thanks so much for your advice.

-Kevin

On 8/7/23 14:38, Josiah Parry wrote:
> Hey Kevin, I don't think you're going to be able to get individual level 
> data from the US Census Bureau. The closest you may be able to get is 
> the current population survey (CPS) which I believe is also available 
> via tidycensus. Regarding your first question, I'm not sure I follow 
> what your objective is with it. I would use a geography of census block 
> groups as the measure of median for census block groups. Otherwise it is 
> unclear how you are defining what a "group of blocks" is.
> 
> On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo 
> mailto:r-sig-geo@r-project.org>> wrote:
> 
> Hello, all,
> 
> I'd like to obtain the median age for a population in a specific group
> of US Decennial census blocks. Here's an example of the problem:
> 
> ## Example of calculating median age of population in census blocks.
> library(tidyverse)
> library(tidycensus)
> 
> counts <- get_decennial(
>       geography = "block",
>       state = "MD",
>       county = "Baltimore city",
>       table = "P1",
>       year = 2020,
>       sumfile = "dhc") %>%
>       mutate(NAME = NULL) %>%
>       filter(substr(GEOID, 6, 11) == "271101" &
>              substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>              )
> 
> ages <- get_decennial(
>       geography = "block",
>       state = "MD",
>       county = "Baltimore city",
>       table = "P13",
>       year = 2020,
>       sumfile = "dhc") %>%
>       mutate(NAME = NULL) %>%
>       filter(substr(GEOID, 6, 11) == "271101" &
>              substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>              )
> 
> I have two questions:
> 
> 1. Is it mathematically valid to multiply the population of a block by
> the median age of that block (in other words, assign the median age to
> each member of a block), then calculate the median of those numbers for
> a group of blocks?
> 
> 2. Is raw data on the ages of individuals available anywhere else in
> the
> census data? I can find tables such as P12, that breaks down the
> population by age ranges or bins, but can't find specific data of
> counts
> per age in years.
> 
> Thanks for your advice and help.
> 
> -Kevin
> 
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org 
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
> 
> 


___
R-sig-Geo mailing list
R-sig-Geo@r-project.org
https://stat.ethz.ch/mailman/listinfo/r-sig-geo

Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Jeff Boggs]

Responses to your questions:
Q1: No. It is not mathematically valid, sadly.

Q2: I do not know, but your intuition that this is a possible solution is 
correct.

I don't use US Census data anymore, but suspect that the data exists. Whether 
they are publicly-available is a different question. I suspect, though, that 
block level age-sex cohort in five-year intervals is available, given this is 
the usual ingredient for a population pyramid. That data could be used to 
calculate a less exact median, if you make some simplifying assumptions.

Best regards,
Jeff



From: R-sig-Geo  on behalf of Kevin Zembower 
via R-sig-Geo 
Sent: Monday, August 7, 2023 14:33
To: r-sig-geo@r-project.org
Subject: [R-sig-Geo] Calculating median age for a group of US census blocks?

Hello, all,

I'd like to obtain the median age for a population in a specific group
of US Decennial census blocks. Here's an example of the problem:

## Example of calculating median age of population in census blocks.
library(tidyverse)
library(tidycensus)

counts <- get_decennial(
 geography = "block",
 state = "MD",
 county = "Baltimore city",
 table = "P1",
 year = 2020,
 sumfile = "dhc") %>%
 mutate(NAME = NULL) %>%
 filter(substr(GEOID, 6, 11) == "271101" &
substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
)

ages <- get_decennial(
 geography = "block",
 state = "MD",
 county = "Baltimore city",
 table = "P13",
 year = 2020,
 sumfile = "dhc") %>%
 mutate(NAME = NULL) %>%
 filter(substr(GEOID, 6, 11) == "271101" &
substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
)

I have two questions:

1. Is it mathematically valid to multiply the population of a block by
the median age of that block (in other words, assign the median age to
each member of a block), then calculate the median of those numbers for
a group of blocks?

2. Is raw data on the ages of individuals available anywhere else in the
census data? I can find tables such as P12, that breaks down the
population by age ranges or bins, but can't find specific data of counts
per age in years.

Thanks for your advice and help.

-Kevin

___
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Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Yes, I see what you mean:

 > median(c(60, 50, 40, 20, 20, 20))
[1] 30
 > median(c(50, 50, 50, 20, 20, 20))
[1] 35
 >

Thanks so much for that clear example.

-Kevin

On 8/7/23 14:45, Sean Trende wrote:
> This is correct on the second question, at least for more recent censuses.  
> On the first question, imagine a block where the ages of three individuals 
> are 60, 50, and 40, and another one where the ages are 20, 20, and 20.  Using 
> your approach you would have 50 * 3 = 150 for the first block, and 20*3 = 60 
> for the second block.  The median of 60 and 150 is 105.  Even dividing that 
> by three you get 35, which is not the correct median age (30).
> 
> -Original Message-
> From: R-sig-Geo  On Behalf Of Josiah Parry
> Sent: Monday, August 7, 2023 2:38 PM
> To: Kevin Zembower 
> Cc: r-sig-geo@r-project.org
> Subject: Re: [R-sig-Geo] Calculating median age for a group of US census 
> blocks?
> 
> Hey Kevin, I don't think you're going to be able to get individual level data 
> from the US Census Bureau. The closest you may be able to get is the current 
> population survey (CPS) which I believe is also available via tidycensus. 
> Regarding your first question, I'm not sure I follow what your objective is 
> with it. I would use a geography of census block groups as the measure of 
> median for census block groups. Otherwise it is unclear how you are defining 
> what a "group of blocks" is.
> 
> On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo < 
> r-sig-geo@r-project.org> wrote:
> 
>> Hello, all,
>>
>> I'd like to obtain the median age for a population in a specific group
>> of US Decennial census blocks. Here's an example of the problem:
>>
>> ## Example of calculating median age of population in census blocks.
>> library(tidyverse)
>> library(tidycensus)
>>
>> counts <- get_decennial(
>>   geography = "block",
>>   state = "MD",
>>   county = "Baltimore city",
>>   table = "P1",
>>   year = 2020,
>>   sumfile = "dhc") %>%
>>   mutate(NAME = NULL) %>%
>>   filter(substr(GEOID, 6, 11) == "271101" &
>>  substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>>  )
>>
>> ages <- get_decennial(
>>   geography = "block",
>>   state = "MD",
>>   county = "Baltimore city",
>>   table = "P13",
>>   year = 2020,
>>   sumfile = "dhc") %>%
>>   mutate(NAME = NULL) %>%
>>   filter(substr(GEOID, 6, 11) == "271101" &
>>  substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
>>  )
>>
>> I have two questions:
>>
>> 1. Is it mathematically valid to multiply the population of a block by
>> the median age of that block (in other words, assign the median age to
>> each member of a block), then calculate the median of those numbers
>> for a group of blocks?
>>
>> 2. Is raw data on the ages of individuals available anywhere else in
>> the census data? I can find tables such as P12, that breaks down the
>> population by age ranges or bins, but can't find specific data of
>> counts per age in years.
>>
>> Thanks for your advice and help.
>>
>> -Kevin
>>
>> ___
>> R-sig-Geo mailing list
>> R-sig-Geo@r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
> 
>   [[alternative HTML version deleted]]
> 
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Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Sean Trende via R-sig-Geo]

This is correct on the second question, at least for more recent censuses.  On 
the first question, imagine a block where the ages of three individuals are 60, 
50, and 40, and another one where the ages are 20, 20, and 20.  Using your 
approach you would have 50 * 3 = 150 for the first block, and 20*3 = 60 for the 
second block.  The median of 60 and 150 is 105.  Even dividing that by three 
you get 35, which is not the correct median age (30).

-Original Message-
From: R-sig-Geo  On Behalf Of Josiah Parry
Sent: Monday, August 7, 2023 2:38 PM
To: Kevin Zembower 
Cc: r-sig-geo@r-project.org
Subject: Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

Hey Kevin, I don't think you're going to be able to get individual level data 
from the US Census Bureau. The closest you may be able to get is the current 
population survey (CPS) which I believe is also available via tidycensus. 
Regarding your first question, I'm not sure I follow what your objective is 
with it. I would use a geography of census block groups as the measure of 
median for census block groups. Otherwise it is unclear how you are defining 
what a "group of blocks" is.

On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo < 
r-sig-geo@r-project.org> wrote:

> Hello, all,
>
> I'd like to obtain the median age for a population in a specific group 
> of US Decennial census blocks. Here's an example of the problem:
>
> ## Example of calculating median age of population in census blocks.
> library(tidyverse)
> library(tidycensus)
>
> counts <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P1",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
> substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> )
>
> ages <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P13",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
> substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> )
>
> I have two questions:
>
> 1. Is it mathematically valid to multiply the population of a block by 
> the median age of that block (in other words, assign the median age to 
> each member of a block), then calculate the median of those numbers 
> for a group of blocks?
>
> 2. Is raw data on the ages of individuals available anywhere else in 
> the census data? I can find tables such as P12, that breaks down the 
> population by age ranges or bins, but can't find specific data of 
> counts per age in years.
>
> Thanks for your advice and help.
>
> -Kevin
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

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Re: [R-sig-Geo] Calculating median age for a group of US census blocks?

[Josiah Parry]

Hey Kevin, I don't think you're going to be able to get individual level
data from the US Census Bureau. The closest you may be able to get is the
current population survey (CPS) which I believe is also available via
tidycensus. Regarding your first question, I'm not sure I follow what your
objective is with it. I would use a geography of census block groups as the
measure of median for census block groups. Otherwise it is unclear how you
are defining what a "group of blocks" is.

On Mon, Aug 7, 2023 at 2:34 PM Kevin Zembower via R-sig-Geo <
r-sig-geo@r-project.org> wrote:

> Hello, all,
>
> I'd like to obtain the median age for a population in a specific group
> of US Decennial census blocks. Here's an example of the problem:
>
> ## Example of calculating median age of population in census blocks.
> library(tidyverse)
> library(tidycensus)
>
> counts <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P1",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
> substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> )
>
> ages <- get_decennial(
>  geography = "block",
>  state = "MD",
>  county = "Baltimore city",
>  table = "P13",
>  year = 2020,
>  sumfile = "dhc") %>%
>  mutate(NAME = NULL) %>%
>  filter(substr(GEOID, 6, 11) == "271101" &
> substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
> )
>
> I have two questions:
>
> 1. Is it mathematically valid to multiply the population of a block by
> the median age of that block (in other words, assign the median age to
> each member of a block), then calculate the median of those numbers for
> a group of blocks?
>
> 2. Is raw data on the ages of individuals available anywhere else in the
> census data? I can find tables such as P12, that breaks down the
> population by age ranges or bins, but can't find specific data of counts
> per age in years.
>
> Thanks for your advice and help.
>
> -Kevin
>
> ___
> R-sig-Geo mailing list
> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>

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[R-sig-Geo] Calculating median age for a group of US census blocks?

[Kevin Zembower via R-sig-Geo]

Hello, all,

I'd like to obtain the median age for a population in a specific group 
of US Decennial census blocks. Here's an example of the problem:

## Example of calculating median age of population in census blocks.
library(tidyverse)
library(tidycensus)

counts <- get_decennial(
 geography = "block",
 state = "MD",
 county = "Baltimore city",
 table = "P1",
 year = 2020,
 sumfile = "dhc") %>%
 mutate(NAME = NULL) %>%
 filter(substr(GEOID, 6, 11) == "271101" &
substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
)

ages <- get_decennial(
 geography = "block",
 state = "MD",
 county = "Baltimore city",
 table = "P13",
 year = 2020,
 sumfile = "dhc") %>%
 mutate(NAME = NULL) %>%
 filter(substr(GEOID, 6, 11) == "271101" &
substr(GEOID, 12, 15) %in% c(3000, 3001, 3002)
)

I have two questions:

1. Is it mathematically valid to multiply the population of a block by 
the median age of that block (in other words, assign the median age to 
each member of a block), then calculate the median of those numbers for 
a group of blocks?

2. Is raw data on the ages of individuals available anywhere else in the 
census data? I can find tables such as P12, that breaks down the 
population by age ranges or bins, but can't find specific data of counts 
per age in years.

Thanks for your advice and help.

-Kevin

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