# rarefaction vs. relative abundance

**URL:** https://forum.qiime2.org/t/rarefaction-vs-relative-abundance/16956
**Category:** General Discussion
**Tags:** rarefaction
**Created:** [October 7, 2020, 3:56pm UTC](https://forum.qiime2.org/t/rarefaction-vs-relative-abundance/16956 "2020-10-07T15:56:00Z")
**Posts on this page:** 1
**Showing post:** 10

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### Author: ![ChrisKeefe](https://forum.qiime2.org/user_avatar/forum.qiime2.org/chriskeefe/32/1907_2.png) [@ChrisKeefe](https://forum.qiime2.org/u/ChrisKeefe)
#### Post date: [October 12, 2020, 5:33pm UTC](https://forum.qiime2.org/t/rarefaction-vs-relative-abundance/16956/10 "2020-10-12T17:33:55Z")

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## core-metrics-phylo

[`core-metrics-phylogenetic`](https://docs.qiime2.org/2020.8/plugins/available/diversity/core-metrics-phylogenetic/) produces all of the non-phylogenetic metrics from `core-metrics` with some phylo metrics thrown in for spice (faith's pd, weighted, and unweighted unifrac). Non-phylo metrics included:

Alpha Diversity:

- Shannon’s diversity index
- Observed Features
- Pielou’s evenness

Beta Diversity:

- Jaccard distance
- Bray-Curtis distance

### Bray-Curtis

Though `bray_curtis` doesn't currently accept relative frequency (RF) data, I don't think passing relative frequency data breaks any assumptions of Bray Curtis, @nathaniel_hubert. [McMurdie & Holmes](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1003531) used RF with Bray Curtis with no issues, and I didn't see any reason not to implement it when I was tinkering with the formula.

If I remember correctly, expediency was the main reason Bray Curtis doesn't accept RF data yet - there were some unexpected test failures with RF data and that method, and we opted to ship what we had rather than delaying release of other methods in favor of that feature.

I'd _love_ to see this enhancement made available in `q2-diversity-lib`, and have opened an [issue](https://github.com/qiime2/q2-diversity-lib/issues/27) to track progress. This isn't currently a high priority for me, but I would be super happy to lend a hand if it's something you're interested in working on!

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