Population Growth Model

[hodedo]

admin said:

Does Plainfield take in more than $0.260 billion per year in taxes like 204? I would be surprised. What I meant was less housing cost in Plainfield = less tax dollars, not what the rate is. What is the rate BTW?

I guess it is easier to complain than to actually go find the facts and report back.

Not complaining...I am asking a question. Thought someone had the rate because they stated it like a fact.

[JB]

Maybe I am a little slow...but where does home price, competition from surrounding suburbs, SB actions/decisions, changing demographics, age of housing stock, age of residents, mobility, private school attendance, taxes, etc. come into play in the model?

It doesn't - that's the beauty of it. It's a mathematical equation that fits the data very well. It's actually one of three completely different approaches I took to show that student population will be grow to the 31,750 range. Google "logistic growth" if you are really interested - it's really quite fascinating.

Recent Examples: 2 developments canceled, 2 new developments not selling, residential permits dropping off cliff

It's simply illogical to say that the 10-12% undeveloped land we currently have will never be used for residential. If we legally turn those areas into Forest Preserves, I'll change my mind.

Carillon adult community (kid restricted) of about 900 units is only development moving forward at this time in Sector G just north of 95th (what about tail end of baby boomer kids passing thru?).

This is great news for D204 - more tax revenue, with no new kids. Our tax rate will drop. I'm all for senior communities and commercial development - all sources of tax revenue which don't add students. Conversely, I'm dead set against rezoning commercial to residential, or low density to high density. Unfortunately, the developers aren't typically moving in that direction.

Great school districts attract people with kids. Look at D203, and the development from teardowns. Old folks moving out, families with kids moving in. That's why they are experiencing crowding issues today. We'd be fools not to look at D203 as the best comparison to what we will look like in the future, provided we continue to demonstrate our committment to academic excellence.

Why would the curve not flatten and/or go down from here?

The curve does flatten - as I said, around 31,750. After that point, we'll experience natural variation about that point. If we screw up our school district by over-crowding it, the graph will probably rise.

First BB will be developed, adding more students and compounding the problem.

Second, developers will petition to re-zone to more affordable high density townhomes, which have a lower price point than single family, yet contain just as many kids. We've seen that at the Plan Commision for awhile now. Townhomes are now the affordable new way to enter D204 - take a look behind Meijers for evidence of that. As SF home prices go up, there will be more and more pressure to build "affordable" housing, which means apartments and townhomes.

I mentioned that the equation did under-predict growth in the year before and the years immediately after Neuqua was opened. I suspect when the 3rd HS is built, we'll see the southern developments take off.

Were there adult communities or high schools 150 years ago? Do 150 year old models really work for high school student projections

You missed my point that this equation describes constrained population growth. In no way is it specific to high school student projections. It is useful because there is an extremely high degree of correlation between observation and prediction. I mentioned 150 years to point out that it is established and has stood the test of time rather well - much like F = MA or E = mc^2

Is history always a predictor of the future?

The entire science of forecasting techniques is based on that premise, and any forecasting model I've implemented at a client site uses it. Forecasting is also based on pattern recognition, which is why the D203 comparison is absolutely correct.

[hodedo]

momto4 said:

hodedo said:

Does it matter what the cost is for St. Francis or Benet? The key is what are the 204 assumptions for enrollment. Kids leave to go to private school is the only fact. What was the number of students that 204 assumed go to private school? The answer is zero right? Also, there is a natural decline in students between elementary and HS in 204 over the years. What number of students did 204 use for that fact? Example, even though the district has been growing for years, we have been losing about 50 less HS seniors per year over the last few years. What assumptions were made by 204 for this fact? (I know the answer - zero as well)

Does Plainfield take in more than $0.260 billion per year in taxes like 204? I would be surprised. What I meant was less housing cost in Plainfield = less tax dollars, not what the rate is. What is the rate BTW?

From the few posts you've made it looks to me like you're just trying to stir things up, but in case you truly are on a fact-finding mission here I thought I'd reply.

Take a look at www.ipsd.org/Uploads/DEC1_HISTORY.pdf

You'll see that following any 9th grade class enrollment to 10/11/12 the decline from 9th grade enrollment to 12th grade is non-existent or small enough to be relatively insignificant. From a quick glance it appears to me that every 9th grade class is bigger than the 8th grade class the year before, which would indicate to me there are more kids who go to private elementary and public HS than the other way around.

The historical enrollment numbers are fact and theorizing about kids going to private schools is not revelant unless some huge new private school is opening.

Using the word billion in your posts looks odd since you are using a 0 with digits only after the decimal. It looks like you are trying to make some sort of point by doing this. With all the references to a $300,000 house we've seen these past few months I've never seen anyone call it a .3 million dollar house. Why are you talking a percentage of a billion instead of using millions as we're actually talking about?

Thanks for these figures. However, as I understand it, the district has used the Cohort method of forecasting future HS needs, and in a high growth environment, that method underestimates HS projections. In a declining growth environment Cohort actually over projects HS enrollment.

From what I have read, the district estimated HS student enrollment based on current enrollment, history and applying the Cohort method to project the future. NIU comes into play here as well; however, I do not know how anyone would ever use a current or another study from NIU. I was also told by an insider, that there was a mysterious difference between the expected versus actual numbers, being told it is an indisputable fact that we lose HS kids between elementary and HS form what was expected (the person was so sure I felt cutoff from further discussion).

Not stirring the pot, but have seen some very strong arguments from others both CFO and individuals, that concern me as a parent who wants to make sure a great district, does not waste money, and puts that money to the best use -- paying teachers. If there is a bubble, that would be a reasonable concern right?

When you see in the papers that we are supposedly now 2000 over capacity now, and that 50% of capacity is ideal fully functional space, I begin asking more questions. When the district will not count 600 contracted for spaces in the Frontier campus, I wonder why? And I was a YES. All my data comes from former YES. I am undecided but leaning NO today.

I think I can agree with the Private school comments, assuming that kids go to private schools early - if they can get in. But after what has happened these last few months, private schools may expand a little to meet higher demand, then you have an impact. There's a lot of interest. Private school vouchers are not off the table either, and if that goes thru there will be a significant change due to new competition.

I will use millions and thousands from here on out if I stay on.

[warriorpride]

hodedo said:

momto4 said:

From the few posts you've made it looks to me like you're just trying to stir things up, but in case you truly are on a fact-finding mission here I thought I'd reply.

Take a look at www.ipsd.org/Uploads/DEC1_HISTORY.pdf

You'll see that following any 9th grade class enrollment to 10/11/12 the decline from 9th grade enrollment to 12th grade is non-existent or small enough to be relatively insignificant. From a quick glance it appears to me that every 9th grade class is bigger than the 8th grade class the year before, which would indicate to me there are more kids who go to private elementary and public HS than the other way around.

The historical enrollment numbers are fact and theorizing about kids going to private schools is not revelant unless some huge new private school is opening.

Using the word billion in your posts looks odd since you are using a 0 with digits only after the decimal. It looks like you are trying to make some sort of point by doing this. With all the references to a $300,000 house we've seen these past few months I've never seen anyone call it a .3 million dollar house. Why are you talking a percentage of a billion instead of using millions as we're actually talking about?

Thanks for these figures. However, as I understand it, the district has used the Cohort method of forecasting future HS needs, and in a high growth environment, that method underestimates HS projections. In a declining growth environment Cohort actually over projects HS enrollment.

From what I have read, the district estimated HS student enrollment based on current enrollment, history and applying the Cohort method to project the future. NIU comes into play here as well; however, I do not know how anyone would ever use a current or another study from NIU. I was also told by an insider, that there was a mysterious difference between the expected versus actual numbers, being told it is an indisputable fact that we lose HS kids between elementary and HS form what was expected (the person was so sure I felt cutoff from further discussion).

Not stirring the pot, but have seen some very strong arguments from others both CFO and individuals, that concern me as a parent who wants to make sure a great district, does not waste money, and puts that money to the best use -- paying teachers. If there is a bubble, that would be a reasonable concern right?

When you see in the papers that we are supposedly now 2000 over capacity now, and that 50% of capacity is ideal fully functional space, I begin asking more questions. When the district will not count 600 contracted for spaces in the Frontier campus, I wonder why? And I was a YES. All my data comes from former YES. I am undecided but leaning NO today.

I think I can agree with the Private school comments, assuming that kids go to private schools early - if they can get in. But after what has happened these last few months, private schools may expand a little to meet higher demand, then you have an impact. There's a lot of interest. Private school vouchers are not off the table either, and if that goes thru there will be a significant change due to new competition.

I will use millions and thousands from here on out if I stay on.

Nice incorrect stating of the numbers (for example 50%).

The private HSs around here are all full - they will have no future impact that is any different from the current & past impact on 204s enrollment numbers.

We can't make 600 kids go to COD, nor can we assume that 600 will go, nor does that reduce capacity by 600, since nobody will go there for a full day.

I think anyone reading your posts would find it hard to believe you are undecided.

[hodedo]

jb said:

Maybe I am a little slow...but where does home price, competition from surrounding suburbs, SB actions/decisions, changing demographics, age of housing stock, age of residents, mobility, private school attendance, taxes, etc. come into play in the model?

It doesn't - that's the beauty of it. It's a mathematical equation that fits the data very well. It's actually one of three completely different approaches I took to show that student population will be grow to the 31,750 range. Google "logistic growth" if you are really interested - it's really quite fascinating.

It's simply illogical to say that the 10-12% undeveloped land we currently have will never be used for residential. If we legally turn those areas into Forest Preserves, I'll change my mind.

This is great news for D204 - more tax revenue, with no new kids. Our tax rate will drop. I'm all for senior communities and commercial development - all sources of tax revenue which don't add students. Conversely, I'm dead set against rezoning commercial to residential, or low density to high density. Unfortunately, the developers aren't typically moving in that direction.

Thanks for the feedback. I will check out the Google. However, having been an operations research graduate, I think you have to look at other factors rather than just the numbers. Both are valid. Bacteria, does not pick up and move to another Petri dish - it dies. I suppose if Naperville is a "destination" city now, then like bacteria we stay until we die, which could take a long while. Just a thought.

I also agree that Naperville should be controlling growth better - like more senior, commercial and parks/preserves.

Thanks

[admin]

I'm all for senior communities

I am not. Didn't the one get a break on paying school taxes since they are not generating any kids?

[JB]

hodedo said:

Thanks for these figures. However, as I understand it, the district has used the Cohort method of forecasting future HS needs

Actually, the current figures are based on current enrollment plus new growth. New growth is calculated by looking at current and planned developments and applying a student generation ratio. The City provides these base on city-wide averages, but the school board used a better method of comparing like properties. For instance, Ashwood Park North is upper end, with a clubhouse, pools, etc. Therefore, they are more comparable to Tallgrass in terms of likely student generation. I looked at both methods, and found a range from 31,500 (city) to 32,000 (D204).

NIU comes into play here as well; however, I do not know how anyone would ever use a current or another study from NIU. I was also told by an insider, that there was a mysterious difference between the expected versus actual numbers

NIU was off because they assumed a 5 bedroom home would generate more kids than a 4 bedroom home. In reality, we just like big homes with extra bedrooms.

..being told it is an indisputable fact that we lose HS kids between elementary and HS form what was expected (the person was so sure I felt cutoff from further discussion).

We see a small portion go to Benet & St. Francis, but to suggest a large-scale loss due to moves makes no sense - where do they end up? For us to consistently, loose HS'ers, someone somewhere would need to take them in. Is there a School District somewhere that is seeing an influx of high school students? And why would they be moving out? This theory doesn't pass the sniff test.

Not stirring the pot, but have seen some very strong arguments from others both CFO and individuals, that concern me as a parent who wants to make sure a great district, does not waste money, and puts that money to the best use -- paying teachers. If there is a bubble, that would be a reasonable concern right?

The best measure for that is cost per pupil - we spend $8,666/pupil, which is less than state average, and less than D203.

When you see in the papers that we are supposedly now 2000 over capacity now, and that 50% of capacity is ideal fully functional space, I begin asking more questions. When the district will not count 600 contracted for spaces in the Frontier campus, I wonder why?

I haven't seen the "now 2,000 over capacity", but would be interested in looking at it if the link is handy to you. Capacity should be at least 3k+3k+3k+1.2k = 10,200. COD adds up to 600 from what I understand.

I think I can agree with the Private school comments, assuming that kids go to private schools early - if they can get in. But after what has happened these last few months, private schools may expand a little to meet higher demand, then you have an impact.

A neighbor asked Benet admin if they were considering that, and they have NO interest in making their school any bigger. I could envision a tuition hike if demand increases - simple supply / demand.

Private school vouchers are not off the table either, and if that goes thru there will be a significant change due to new competition.

Agreed. But, it would have to pass, and then you'd have to build your schools. This isn't something that will happen in the near future.

[JB]

admin said:

I'm all for senior communities

I am not. Didn't the one get a break on paying school taxes since they are not generating any kids?

Not sure. Something to look into after 3/21 though.

[d204mom]

hodedo said:

jb said:

It doesn't - that's the beauty of it. It's a mathematical equation that fits the data very well. It's actually one of three completely different approaches I took to show that student population will be grow to the 31,750 range. Google "logistic growth" if you are really interested - it's really quite fascinating.

It's simply illogical to say that the 10-12% undeveloped land we currently have will never be used for residential. If we legally turn those areas into Forest Preserves, I'll change my mind.

This is great news for D204 - more tax revenue, with no new kids. Our tax rate will drop. I'm all for senior communities and commercial development - all sources of tax revenue which don't add students. Conversely, I'm dead set against rezoning commercial to residential, or low density to high density. Unfortunately, the developers aren't typically moving in that direction.

Thanks for the feedback. I will check out the Google. However, having been an operations research graduate, I think you have to look at other factors rather than just the numbers. Both are valid. Bacteria, does not pick up and move to another Petri dish - it dies. I suppose if Naperville is a "destination" city now, then like bacteria we stay until we die, which could take a long while. Just a thought.

I also agree that Naperville should be controlling growth better - like more senior, commercial and parks/preserves.

Thanks

Wow! What a great analysis! You must have a phd in biochemistry, hodedo!

[JB]

Thanks for the feedback. I will check out the Google. However, having been an operations research graduate, I think you have to look at other factors rather than just the numbers. Both are valid. Bacteria, does not pick up and move to another Petri dish - it dies. I suppose if Naperville is a "destination" city now, then like bacteria we stay until we die, which could take a long while. Just a thought.

I also agree that Naperville should be controlling growth better - like more senior, commercial and parks/preserves.

Thanks

Are you suggesting bacteria migrate?

Sorry, bad cross-reference to a Monty Python thread hijack we had last night ;D AE is laughing somehwere.

I started along the multiple-regression against external factors path you alluded to, but hit dead ends. That's when I came across the logistic growth work. Because of the good fit with observation, I persued that route. It's note a petri-dish bacteria model. In fact it's used in animal and human populations

[admin]

D204Mom, watch the personal attacks.

[d204mom]

Sorry, Topher and Hodedo. I'll be nice.

[d204mom]

Quote from jb:
"A neighbor asked Benet admin if they were considering that, and they have NO interest in making their school any bigger. I could envision a tuition hike if demand increases - simple supply / demand."

That is an interesting point jb. I know several no voters in my neighborhood that send their children to private school. ITRF, and tuition does increase due to the increased demand, I wonder if that will completely negate any property tax savings for them.

[Arch]

jb said:

admin said:

I am not. Didn't the one get a break on paying school taxes since they are not generating any kids?

Not sure. Something to look into after 3/21 though.

Even now, I would be for any thing that USED up the remaining land and did NOT generate kids. Forest preserves, retirement communities, commercial places, a new 'south mall', recreational parks, etc.

They get a tax credit usually in one form or another anyway (like Lexus for approx 125 grand for planting a few trees along their border... Wonder what they paid the landscaper to put them in, huh?)

[Arch]

People with money in hand makes old impossible ideas possible again.