John Paul Helveston
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jhelvy.bsky.social
John Paul Helveston
@jhelvy.bsky.social
11K followers 2.8K following 560 posts
Systems Eng Prof @ GWU 🦛 | Director, Data Analytics MS Program | EVs 🔋🚗 | Low Carbon Tech | Choice Modeling | Survey Research | China | US-China Policy | #rstats | #reproducibility | #opensource | Father | opinions own
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jhelvy.bsky.social
Good point. It's likely that the CLTC may reflect higher ranges than would be achieved in the US, by as much as 30% (which may entirely be due to real differences in driving cycles between US & China).

Here's an adjusted figure with Chinese ranges reduced by 30%

github.com/jhelvy/us-ch...
November 1, 2025 at 12:00 AM
jhelvy.bsky.social
EV % of new vehicle sales in 2024:

🇨🇳 China: 46.7%

🇺🇸 USA: 9.8%

In 2024, China exported 1.28 million PEVs—nearly matching total U.S. domestic PEV sales.
Stacked bar chart showing annual vehicle sales in China from 2016 to 2024, divided into three categories: ICEV (internal combustion engine vehicles) in gray, PHEV (plug-in hybrid electric vehicles) in dark green, and BEV (battery electric vehicles) in bright green. ICEV sales peaked at approximately 25 million in 2017, then steadily declined to about 15 million by 2024. Meanwhile, total PEV sales (PHEV and BEV combined) grew from 0.51 million in 2016 to 12.86 million in 2024, with BEV sales comprising the majority of this growth.
October 30, 2025 at 6:18 PM
jhelvy.bsky.social
Chinese EVs can charge at 1 MW, meaning 250-325 miles of range in just 5 min.

🇨🇳 Highest-range Chinese BEV (left): Zeekr 001, with 645 miles of range for $56k

🇺🇸 Highest-range U.S. BEV (right): Lucid Air, with 517 miles of range for $169k
Orange Zeekr 001 Silver Lucid Air
October 30, 2025 at 6:18 PM
jhelvy.bsky.social
🇨🇳 Chinese OEMs now make superior EVs at far lower prices than 🇺🇸 U.S. OEMs.

China has 52 BEV models with 400+ mile ranges, most under $50k. The U.S. has 4, all priced above $75k.
Scatter plot comparing price versus range for 2024 battery electric vehicles in China (red dots) and the USA (blue dots) across three categories: Cars, SUVs, and Pickup Trucks. Chinese EVs consistently cluster at lower price points across all range categories, with many options under $40,000, while US EVs are predominantly priced above $40,000. Range extends from approximately 100 to 500+ miles for most vehicles, with prices spanning from under $10,000 to over $120,000.
October 30, 2025 at 6:18 PM
jhelvy.bsky.social
When the data tells a clear story, we all make the same chart 📊

Left: From @hannahritchie.bsky.social's ourworldindata piece (Oct 24, 2025) on EV sales:
ourworldindata.org/electric-car...

Right: a slide from a talk I gave at Princeton in Feb. 2025
jhelvy.github.io/slides-old/2...
October 30, 2025 at 1:37 AM
jhelvy.bsky.social
Happy Sic Semper Tyrannis Day!
Image of the Virginia state flag, which contains the latin words Sic Semper Tyrannis
October 18, 2025 at 4:49 PM
jhelvy.bsky.social
#Rstats, #python, #julialang
October 8, 2025 at 10:49 AM
jhelvy.bsky.social
Angry goose meme: "why can't they sell the harvest?!"
September 29, 2025 at 12:30 AM
jhelvy.bsky.social
Looks like we'll just have to watch Bluey on YouTube from now on
Screenshot of my cancellation of Disney plus. Message says "I am cancelling because Disney is run by a coward too afraid to stand up to fascism"
September 20, 2025 at 2:36 PM
jhelvy.bsky.social
One week til I present on our survey platform surveydown at #positconf! If you've ever wanted a #Quarto for surveys, this is it! 🚀

#rstats
surveydown.org
line chart of surveydown repo, which went from ~5 stars to 125+ in 18 months 🚀
September 9, 2025 at 10:14 AM
jhelvy.bsky.social
Seems bad
August 2, 2025 at 10:04 AM
jhelvy.bsky.social
Whole lotta tiki torch energy from this one
A fascist
July 22, 2025 at 12:21 PM
jhelvy.bsky.social
I feel like posting my favorite state flag today, for no particular reason. Isn't it beautiful!
Virginia State flag, which reads sic semper thrannis
June 14, 2025 at 3:53 PM
jhelvy.bsky.social
More and more people are trying out our #surveydown survey platform! 🚀

If you work with surveys, give it a look: an open-source, fully reproducible, programmable, and markdown-based survey platform, built with ❤️, #rstats, #shiny, and #quarto

surveydown.org
June 6, 2025 at 11:14 PM
jhelvy.bsky.social
This is a very cool study

Drones can have up to 94% lower energy consumption per package than other vehicles
June 5, 2025 at 9:36 AM
jhelvy.bsky.social
A story in four parts:

Ph.D. Student, Postdoc, Assistant Professor, Tenured!
Me as a phd student Me as a postdoc Me as an assistant professor Me as an associate professor
May 20, 2025 at 11:12 PM
jhelvy.bsky.social
My student's graduation cap is 🔥🔥🔥
#rstats
A decorated graduation cap with a coding theme in R. The cap is dark blue/navy with a rhinestone or jeweled border. On top of the cap is text written in a code-like format that reads: library(EMSE) #sust graduate_BS(GWU, 2025) success<-TRUE The cap is adorned with white roses arranged along the top edge and has a large white satin bow attached at the bottom.
May 13, 2025 at 2:06 PM
jhelvy.bsky.social
We're in for a confusing summer. Oil prices down ~15% YTD will ease inflation metrics while the prices of everything else increase. R's will cheer victory while ignoring the collapsing economy, and US oil producers will struggle to survive. Cheaper gas, collapsing economy, confusing times.
# Crude Oil Price Summary (Yahoo Finance Data) This chart displays the year-to-date (YTD) performance of Crude Oil June 25 futures (CL=F), showing a pronounced downward trend. Starting around $75 per barrel in January, prices briefly peaked near $80 before steadily declining to the current $59.98, representing a significant 15.48% YTD decrease. The most dramatic drop occurred in April, when prices fell sharply from around $70 to the low $60s, with current trading showing continued weakness at $59.98 (-0.73% for the session).
April 30, 2025 at 12:27 PM
jhelvy.bsky.social
Homer Simpson meme with Bart. Top caption: It’s the worst attack on voting rights in America. Bottom caption: It’s the worst attack on voting rights in America so far.
April 10, 2025 at 11:43 PM
jhelvy.bsky.social
New blog post! 🚨

The #surveydown 📦 now has shiny gadgets to make it easier to insert pages and questions into your surveys! Check out the post by @pingfanhu.bsky.social to see more

surveydown.org/blog/2025-04...

#rshiny #rstats #quarto
April 9, 2025 at 6:48 PM
jhelvy.bsky.social
Made an app so you can view daily updates of this chart & compare other administrations and metrics like unemployment and inflation 🤓

It updates daily, so check it tomorrow to see today's continued US market collapse 🤠

jhelvy.github.io/potus-econ-s...

Built with #rstats #shinylive #quarto
Screenshot of my POTUS Economic Scorecard app showing S&P 500 performance during the first 100 days following presidential inaugurations. The graph reveals Biden (2021) at +8.5%, Obama (2013) at +7%, Trump (2017) at +5%, and Trump (2025) at -16.1%. The interface includes options to select different economic indicators, adjust time periods, and filter by political party. The data visualizes a significant market decline during the current Trump administration compared to positive performances in previous administrations' early days.
April 7, 2025 at 7:46 PM
jhelvy.bsky.social
My chart made it to the #HandsOff protest!
The image shows a protest sign with the words "STOP MAKING AMERICA POORER & SICKER AGAIN" written in red and black letters. The sign includes a graph labeled "S&P 500 Performance During First 100 Days In Office" that compares stock market performance during the first 100 days of different presidential terms. The graph shows performance lines for several presidencies, normalized to inauguration day (where 0% represents the S&P 500 value on day 0): - Biden (2021): showing positive performance around +8.6% - Obama (2013): showing positive performance around +7.0% - Trump (2017): showing positive performance around +4.9% - Trump (2025): showing significant negative performance of approximately -16.1% The data source noted on the chart is "Yahoo Finance via [quantmod] R package" with a source link to GitHub. The sign appears to be held by someone at what seems to be an outdoor gathering or protest, with other people visible in the background.
April 6, 2025 at 1:02 AM
jhelvy.bsky.social
I had to adjust the y-axis after remaking this chart only one day later 🫠
Same stock market plot as in the quoted post, but updated one day later, which shows the Trump 2025 value now down -16%
April 5, 2025 at 6:15 PM
jhelvy.bsky.social
It's almost like the country is being run by a convicted felon who's bankrupted 6 businesses or something

Made with #rstats
The image shows a line graph titled "S&P 500 Performance During First 100 Days in Office," displaying the stock market performance during the first 100 days of different presidential administrations. The graph is normalized to Inauguration Day (0% = S&P 500 value on day 0). The chart tracks four different presidential terms: Biden (2021): Blue line ending at +8.55% Obama (2013): Blue line ending at +7.04% Trump (2017): Red line ending at +4.97% Trump (2025): Red line ending at -10.79% The graph shows that Biden's first 100 days saw the strongest S&P 500 performance (+8.55%), followed by Obama's second term (+7.04%), and Trump's first term (+4.97%). In contrast, Trump's second term (2025) shows a significant decline, with the S&P 500 down -10.79% after the first 72 days. The data appears to have been pulled using the {quantmod} R package, with the source noted as https://github.com/jhelvy/charts.
April 3, 2025 at 9:50 PM
jhelvy.bsky.social
Did not know the software processing James Web Telescope data was #opensource 😲

At the first ever GW open source conference #gwoscon
Photo of Steve Crawford,  program executive for NASA's Open Source Science Initiative, giving the keynote for the GW open source conference, 2025
March 24, 2025 at 1:39 PM