Ranking US Cities by Venture Capital - Revision history

Ed: /* Third Rebuild */

2021-03-07T17:22:39Z

Third Rebuild

2021-02-10T03:49:15Z

Third Rebuild

2021-01-22T15:56:02Z

Artifacts and Facts

2021-01-21T01:41:40Z

City Growth Rates

2021-01-21T01:40:20Z

Artifacts and Facts

2021-01-21T00:27:57Z

Third Rebuild

2021-01-19T03:38:07Z

Project Description

2021-01-13T19:41:27Z

City Growth Rates

2021-01-13T17:47:29Z

Third Rebuild

2021-01-12T18:29:35Z

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 ==Third Rebuild==
-The third rebuild uses [[VCDB20]] and covers up until the end of 2020. It combines Geocoding with city information when geocoding is unavailable. The code is in:
+The third rebuild uses [[VCDB20]] and covers up until the end of 2020. It combines geocoding with city information when geocoding is unavailable. The code is in:
   E:\projects\vcdb20\Ranking.sql

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 The build implements the following decisions:
-*Placenames are from geocoding where possible and city names where not. ACS and Tigergeog are joined using Geoid where possible.
+*'''Placenames''' are from geocoding where possible and '''city''' names where not.
-*The ranking uses only growth VC (i.e., growthflag==1 on '''round''').
+*The '''ACS''' and '''Tigergeog''' tables are joined in using '''geoid''', which is determined from '''placenames''' (where possible).
-*Places must have non-zero VC in at least one year between 1980 and 2020, inclusive, to be included.
+*A startup received growth VC if it one of its round stages was seed, early or later.
 ===Artifacts and Facts===

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 *Fraction of data with disclosed amounts
 *Turnover of the Top 10, 20, 50, 100
-*Correlations between the three component measures
+*Correlations between the three component measures (top 200?)
 *Cumulative Percentage of Growth VC, new deals, and alive by city (top 10, 20, 50, and 100) over time
 *Average Growth rate of Growth VC, new deals, and alive by city (top 10, 20, 50, and 100) over time

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   (47 rows)
-Note that if we exclude 2000 (i.e. consider 2001 to 2017 inclusive), the overall average growth rate drops to 0.2812, and some cities, like Houston, have materially lower growth rates. It is worth noting that Houston had one big up year in 2013, where growth VC investment levels where 2.168 times the previous year, but then suffered a about a 50% mean reversion in the following years. Without 2013, Houston's average 2001 to 2017 growth rate is - -0.0197349989630022.
+Note that if we exclude 2000 (i.e. consider 2001 to 2017 inclusive), the overall average growth rate drops to 0.2812, and some cities, like Houston, have materially lower growth rates. It is worth noting that Houston had one big up year in 2013, where growth VC investment levels where 2.168 times the previous year, but then suffered a about a 50% mean reversion in the following years. Without 2013, Houston's average 2001 to 2017 growth rate is -0.0197349989630022.
           city         | state |         avg

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 The main artifacts are:
-*The Top 200 for 2020
+*The Top 100 (and 200) for 2020
 *A graph of total US growth VC investment 1980-2020
 Other artifacts/facts:
 *Fraction of data that is geocodable or has a valid placename
-*Turnover of the Top 10, 20, 50, 100, 200
+*Fraction of data with disclosed amounts
-*Correlation between measures?
+*Turnover of the Top 10, 20, 50, 100
-*Cumulative Percentage of Growth VC
+*Correlations between the three component measures
 ==Second (Complete) Rebuild==

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 This project was initially undertaken in the summer of 2017 and resulted in a full report on 2016. See: [[US Startup City Ranking]].
-The data was then updated for 2017 and 2018 (Q1 and Q2), which resulted in a ranking spreadsheet and document, but not a full report in the first rebuild using [[Restoring vcdb3|vcdb3]]. It was then updated again to include the first half of 2019, using [[Vcdb4]]. The third update includes everything up to the end of 2020 and uses [[Vcdb20]].
+The data was then updated for 2017 and 2018 (Q1 and Q2), which resulted in a ranking spreadsheet and document, but not a full report in the first rebuild using [[Restoring vcdb3|vcdb3]]. It was then updated again to include the first half of 2019, using [[Vcdb4]]. The third update includes everything up to the end of 2020 and uses [[VCDB20]].
 ==Third Rebuild==

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 A code section was added to E:\project\vcdb3\Ranking.sql to explore city growth rates.
-The main problem with estimating the average of <math>\frac{dollars_t - dollars_{t-1} }{dollars_{t-1}}</math>, where dollars is growth VC dollars invested in a city-year, is a truncation issue.  <math>dollars_{t-1}</math> is often zero, and it is impossible for value to be below -100% while it can be above +100%.
+The main problem with estimating the average of <math>\frac{dollars_t - dollars_{t-1} }{dollars_{t-1}}</math>, where dollars is growth VC dollars invested in a city-year, is a truncation issue.  <math>dollars_{t-1}</math> is often zero, and it is impossible for the resulting value to be below -100% while it can be above +100%.
 I experimented with various ways to limit this issue, including considering: