Cryptocurrency crashed during 2018, after Bitcoin was around $15,000 when Scott Alexander made his 2018 predictions.

Judge as of 2019-01-22. Two parts: (a) cryptocurrency prices crashed during 2018; (b) Bitcoin was around $15,000 when he posted his 2018 predictions. True: Bitcoin and the broader crypto market fell sharply in 2018 (e.g. Bitcoin ending near $3,500–4,000) and Bitcoin's price on his 2018 prediction post date was roughly $13,000–17,000. Mostly true: the crash is confirmed and the price at posting was somewhat outside that band (e.g. $11,000–13,000 or $17,000–19,000). Mixed: only one part holds. Mostly false: there was no crash of the scale implied, or the price at posting was far from $15,000. False: crypto did not fall in 2018.

Set before the research began.

1. E1 Down More than 70% in 2018, Bitcoin Closes Its Worst Year on Record CoinDesk · 2 January 2019

   “The leading cryptocurrency's 2018 performance of a more than 70-percent depreciation from its opening price of $13,062 is considerably worse than the previous record holder”

2. E2 Bitcoin fell 37 percent in November, erasing $70 billion from industry CNBC · 30 November 2018

   “The digital currency is now down more than 70 percent since the start of 2018 and 80 percent from its all-time high hit late last year.”

3. E3 Bitcoin price history 2009–2026 | Key milestones | Capital.com EU Capital.com · 13 November 2025

   “BTC fell from around $13,400 in January to about $3,800 by year-end – a decline of around 70%.”

4. E4 Bitcoin Returns in 2018 by Month and Day | Maketo Maketo

   “Closed - $3,747.39”

5. E5 Down More than 70% in 2018, Bitcoin Closes Its Worst Year on Record CoinDesk · 2 January 2019

   “Now having closed the year at the price of $3,747, 2018 will go in the record books as bitcoin's worst performing 12-month stretch ever in terms of price.”

6. E6 Down More than 70% in 2018, Bitcoin Closes Its Worst Year on Record CoinDesk · 2 January 2019

   “Bitcoin's price just finished its worst performing year ever, closing 2018 at a more than 70 percent lower price than its yearly open.”

7. E7 Bitcoin Returns in 2018 by Month and Day | Maketo Maketo

   “Bitcoin fell 72.94% in 2018, from $13,850.49 at the year's open to $3,747.39 at its last recorded close as of .”

8. E8 Down More than 70% in 2018, Bitcoin Closes Its Worst Year on Record CoinDesk · 2 January 2019

   “at least the year in which bitcoin prices dropped more than 80 percent and the broarder market lost nearly $700 billion of total capitalization is over.”

9. E9 End of year crypto roundup: How did Bitcoin perform in 2018? The Next Web (TNW) · 28 December 2018

   “As of December last week, BTC is trading at $3,898, marking a 70 percent drop in value since the start of the year.”

10. E10 End of year crypto roundup: How did Bitcoin perform in 2018? The Next Web (TNW) · 28 December 2018

    “BTC rallied for the first week of January gaining 36 percent breaking at $17,527 on January 7, the highest market price it would see for the rest of the year.”

11. E11 [BTC] Bitcoin December 2018 USD price history - Best Crypto Checker Best Crypto Checker · 30 October 2021

    “During December 2018, Bitcoin price declined by -8.44%, starting at $4,041.27 and closing the month at $3,700.31.”

12. E12 比特币2018年价格走势图 btc126

    “| 时间 | 最高价($) | 最低价($) | |---|---|---| | 2018-12-31 | 3868.74 | 3725.87 |”

Part (a) is well supported. CoinDesk reports that bitcoin closed 2018 at $3,747, more than 70% below its yearly open, in its worst year on record, while the broader market lost nearly $700 billion in total value (E5, E6, E8). CNBC and TNW report similar declines of about 70 percent or more since the start of 2018 (E2, E9). For part (b), the evidence does not give the date of the 2018 prediction post. Bitcoin opened 2018 around $13,000–13,850 and peaked at $17,527 on January 7 (E1, E7, E10), which fits a price near $15,000 in early January, but the price on the posting date cannot be confirmed directly.