> For the complete documentation index, see [llms.txt](https://docs.candelacharts.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.candelacharts.com/investing/market-valuation-and-on-chain/shiller-pe-ratio/faqs.md).

# FAQs

<details>

<summary>Where does the data for this ratio come from?</summary>

The tool pulls the official CAPE10 series from Multpl, which is based on the research of Yale Professor Robert Shiller.

</details>

<details>

<summary>Why is the "Historical Mean" set to 17.0?</summary>

The long-term average of the Shiller PE since 1881 is approximately 17.0. Some investors prefer to use a higher mean (e.g., 19-20) for the post-WWII era.

</details>

<details>

<summary>Does a high Shiller PE mean the market will crash immediately?</summary>

No. Valuations are not timing tools; markets can stay overvalued for years. It is a measure of long-term risk and future return expectations.

</details>

<details>

<summary>What is the difference between Monthly and Yearly resolution?</summary>

Monthly provides more tactical data points, while Yearly is better for high-level secular trend analysis and historical backtesting.

</details>

<details>

<summary>How should I interpret the "Deviation" stat in the dashboard?</summary>

It shows how far the current ratio is from the Historical Mean. A +50% deviation suggests the market is significantly stretched relative to its historical norm.

</details>


---

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