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Multiple testing for modern data: structure, curation, and replicability Eugene Katsevich Department of Statistics Stanford University March 12, 2019 1 / 45
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Page 1: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Multiple testing for modern data:structure, curation, and replicability

Eugene Katsevich

Department of StatisticsStanford University

March 12, 2019

1 / 45

Page 2: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

A modern data set

(Image source: Nature) 2 / 45

Page 3: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

UK Biobank data

Extensive data on 500,000 individuals, including

I Genotypes

I Diseases (from electronic health records)

I Blood pressure and other clinical diagnostics

I Socioeconomic variables

I Environmental risk factors

I Imaging data

I Diet and exercise questionnaires

I . . .

3 / 45

Page 4: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Genotype data

A genotype is an individual’s allele at agiven single nucleotide polymorphism (SNP).

Genotypes measured at 1,000,000 SNPs.

(Image source: Google)

4 / 45

Page 5: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Genotype data have spatial structure

Nearby SNPs are strongly correlated with each other.

Genome •SNP1

•SNP2

•SNP3

•SNP4

•SNP5

•SNP6

•SNP7

•SNP8

•SNP9

5 / 45

Page 6: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Disease data

Disease codes from hospital episodes,using International Classification of Diseases (ICD-10).

ICD-10 is very comprehensive and includes 20K codes.

(Image source: Google)

6 / 45

Page 7: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Disease data

Disease codes from hospital episodes,using International Classification of Diseases (ICD-10).

ICD-10 is very comprehensive and includes 20K codes.

(Image source: Google)

6 / 45

Page 8: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Disease data have tree structure

GoutRheumatoid

arthritis

Ankylosingspondylitis

Spondylosis

Inflammatorypolyarthropathies

Spondylopathies

Diseases of the musculoskeletal systemand connective tissue

7 / 45

Page 9: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

UK Biobank: a complex multiple testing problem

•SNP1 •SNP2 •SNP3 •SNP4 •SNP5 •SNP6 •SNP7 •SNP8 •SNP9

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Type-I error rates like the false discovery rate (FDR)controlled for replicability. 8 / 45

Page 10: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Findings from modern data sets often need curation

Manual curation (exploration):Domain experts search for interesting patterns in the data.

Automatic curation (filtering):Structured hypotheses often lead to redundant findings;filtering is commonly used to reduce redundancy.

Curation may conflict with replicability!

9 / 45

Page 11: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Findings from modern data sets often need curation

Manual curation (exploration):Domain experts search for interesting patterns in the data.

Automatic curation (filtering):Structured hypotheses often lead to redundant findings;filtering is commonly used to reduce redundancy.

Curation may conflict with replicability!

9 / 45

Page 12: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Phenome-wide association studies (PheWAS)

•SNP1 •SNP2 •SNP3 •SNP4 •SNP5 •SNP6 •SNP7 •SNP8 •SNP9

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Page 13: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Rejection sets in phenotype space can be redundant

GoutRheumatoid

arthritis

Ankylosingspondylitis

Spondylosis

Inflammatorypolyarthropathies

Spondylopathies

Diseases of the musculoskeletal systemand connective tissue

cyan nodes: non-null; red nodes: null; shaded nodes: rejected.

11 / 45

Page 14: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Redundancy can be fixed by applying the outer nodes filter

GoutRheumatoid

arthritis

Ankylosingspondylitis

Spondylosis

Inflammatorypolyarthropathies

Spondylopathies

Diseases of the musculoskeletal systemand connective tissue

cyan nodes: non-null; red nodes: null; shaded nodes: rejected.

Yekutieli (JASA, 2008)

12 / 45

Page 15: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Outer nodes filter may inflate the FDR

GoutRheumatoid

arthritis

Ankylosingspondylitis

Spondylosis

Inflammatorypolyarthropathies

Spondylopathies

Diseases of the musculoskeletal systemand connective tissue

cyan nodes: non-null; red nodes: null; shaded nodes: rejected.

Yekutieli (2008)

13 / 45

Page 16: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Existing options to control outer nodes FDR are limited

I Yekutieli proposed a procedure and bounded itsouter nodes FDR, but only under independence.

I Structured Holm procedure1 controls FWER on DAGs.It allows arbitrary dependence but is conservative.

1Meijer and Goeman (2016)14 / 45

Page 17: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Similar problems arise in other applications as well

I Genome-wideassociation studies2

I Imaging applicationssuch as fMRI3

I Gene Ontologyenrichment analysis4

•SNP1 •SNP2 •SNP3 •SNP4 •SNP5 •SNP6 •SNP7 •SNP8 •SNP9

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2Siegmund, Zhang, Yakir (2011)3Pacifico et al (2004), Heller et al (2006), Sun et al (2015)4Goeman and Buhlmann (2007), Meijer and Goeman (2016)

15 / 45

Page 18: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

A general problem

Filtering may inflate the FDR, and must be accounted for.

p-values Filtered rejections

Initial rejectionsBH Filter

Partial solutions exist, but a general-purpose solution is lacking.

Focus of this talk

Reconciling curation with replicability formodern data analysis pipelines.

Goeman and Solari (2011), Berk et al (2013), Taylor andTibshirani (2015), . . .

16 / 45

Page 19: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Preview: Reconciling curation with replicability

Part I (automatic curation): For any pre-specified filter, wepropose Focused BH5 to control the FDR after filtering.

p-values Filtered rejections

Initial rejectionsBH Filter

Filter Focused BH

BH

Part II (manual curation):We propose simultaneousselective inference6 toallow directed explorationwhile bounding FDP whp.

A

B C

0.0

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0.8

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Hypothesis Index

Fals

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Simultaneous Selective Bound (KR19) Simultaneous Bound (GS11) True FDP

5K., Sabatti, Bogomolov (arXiv, 2019+)6K. and Ramdas (AOS, in revision, 2019+), K. and Sabatti (AOAS, 2019)

17 / 45

Page 20: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Preview: Reconciling curation with replicability

Part I (automatic curation): For any pre-specified filter, wepropose Focused BH5 to control the FDR after filtering.

p-values Filtered rejections

Initial rejectionsBH Filter

Filter Focused BH

BH

Part II (manual curation):We propose simultaneousselective inference6 toallow directed explorationwhile bounding FDP whp.

A

B C

0.0

0.2

0.4

0.6

0.8

1.0

0 10 20 30 40 50

Hypothesis Index

Fals

e D

isco

very

Pro

port

ion

Bou

nd

Simultaneous Selective Bound (KR19) Simultaneous Bound (GS11) True FDP

5K., Sabatti, Bogomolov (arXiv, 2019+)6K. and Ramdas (AOS, in revision, 2019+), K. and Sabatti (AOAS, 2019)

17 / 45

Page 21: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Part I: Controlling FDR while filtering

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Page 22: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

A general definition of a filter

Hypotheses H = (H1, . . . ,Hm) and p-values p = (p1, . . . , pm).

Definition

Given R ⊆ H and p ∈ [0, 1]m, a filter F is any mapping

F : (R,p) 7→ U , such that U ⊆ R.

For example,

I F is theouter nodes filter;

I R is the set ofrejected nodes;

I U is the set ofouter nodes.

GoutRheumatoid

arthritis

Ankylosingspondylitis

Spondylosis

Inflammatorypolyarthropathies

Spondylopathies

Diseases of the musculoskeletal systemand connective tissue

19 / 45

Page 23: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Adjusting the FDR for filtering

The false discovery proportion (FDP) of a set U ⊆ H is

FDP(U) =|U ∩ H0||U|

,

where H0 ⊆ H is the set of nulls.

Definition

Given a filter F, the false filtered discovery rate of a testingprocedure (mapping p 7→ R∗) is

FDRF = E[FDP(U∗)] = E[FDP(F(R∗,p))].

Given a filter F and a pre-specified target FDR level q, our goal isto design a testing procedure for which FDRF ≤ q.

20 / 45

Page 24: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Adjusting BH to account for filtering

For a p-value cutoff t ∈ [0, 1], consider R(t) = {j : pj ≤ t}.

BH procedure

BH employs the FDP estimate (Storey, 2002)

FDPBH(t) =m · t|R(t)|

;

choosing the threshold

t∗BH = max{t ∈ [0, 1] : FDPBH(t) ≤ q}.

We are interested instead in U(t) = F({j : pj ≤ t},p).

BH too optimistic in counting discoveries: |R(t)| � |U(t)|.

21 / 45

Page 25: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Adjusting BH to account for filtering

Instead of

FDPBH(t) =m · t|R(t)|

,

correct the denominator and define

FDP(t) =m · t|U(t)|

=m · t

|F({j : pj ≤ t},p)|.

We keep the numerator as is, since |U(t) ∩H0| ≤ |R(t) ∩H0|.

22 / 45

Page 26: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focused BH procedure

Data: p-values p1, . . . , pm, filter F, target level qfor t ∈ {0, p1, . . . , pm} do

Compute FDP(t) =m · t

|F({j : pj ≤ t},p)|;

end

Compute t∗ ≡ max{t ∈ {0, p1, . . . , pm} : FDP(t) ≤ q};Result: R∗ = {j : pj ≤ t∗}.

I Focused BH is a general-purpose way of dealing with filters;note that F can be a black box.

I When F does nothing, Focused BH reduces to BH.

I Procedure can be expanded to filters that prioritize rejections.

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Page 27: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focused BH provably controls FDRF

A filter F is monotonic if for R1 ⊇ R2 and p1 ≤ p2, we have

|F(R1,p1)| ≥ |F(R2,p2)|.

A filter is simple if |F(R,p)| is independent of p.

Theorem (K., Sabatti, Bogomolov)

Focused BH controls FDRF if either

1. p-values are independent, F is simple or monotonic.

2. p-values are “positively dependent” (PRDS), F is monotonic.

I Proof for item 1 inspired by Benjamini and Bogomolov (2014);

I Proof for item 2 inspired by Blanchard and Roquain (2008).

Simulations suggest Focused BH is robust.

24 / 45

Page 28: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Specializing to the outer nodes filter

Corollary

Focused BH controls the outer nodes FDR on trees ifthe p-values are positively dependent.

Proof: The outer nodes filter is monotonic on trees.

Focused BH is the first procedure provably controllingouter nodes FDR under dependence.

25 / 45

Page 29: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Specializing to the outer nodes filter

Corollary

Focused BH controls the outer nodes FDR on trees ifthe p-values are positively dependent.

Proof: The outer nodes filter is monotonic on trees.

Focused BH is the first procedure provably controllingouter nodes FDR under dependence.

25 / 45

Page 30: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Improving the power of Focused BH

The numerator m · t in

FDP(t) =m · t

|F({j : pj ≤ t},p)|

can be a conservative estimate of V (t) = |U(t) ∩H0|.

Can improve procedure’s power by tightening FDP estimate, e.g.

Voracle(t) = E[V (t)] ≤ m · t.

26 / 45

Page 31: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Improving the power of Focused BH by permutations

Let p be a “permuted” version of p. Then,

E[V (t)] = E [|F({j : pj ≤ t},p) ∩H0|]≈ E[|F({j : pj ≤ t}, p) ∩H0|]≤ E[|F({j : pj ≤ t}, p)|].

Given permutations p1, . . . , pB , define

Vperm(t) =1

B

B∑b=1

|F({j : pbj ≤ t}, pb)|.

No theoretical results yet, but performs well in simulations.

27 / 45

Page 32: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simulation: Setup

Graph structure: Forest of 20 binary trees of depth 6,with m = 1260 total nodes.

Data generating mechanism:

I 21 non-null leaves (out of 640), 98 total non-nulls;

I Leaf nodes get independent p-values;

I Internal nodes get p-values by applyingSimes global test to their leaf descendants.

Filter: Outer nodes filter.

28 / 45

Page 33: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simulation: Methods compared

I BH (targeting pre-filter FDR at level q = 0.1)

I Structured Holm7 (targeting FWER at level q = 0.1)

I Yekutieli8 (targeting post-filter FDR at level q = 0.1)I Focused BH (targeting post-filter FDR at level q = 0.1)

I Original versionI Permutation versionI Oracle version

7Meijer and Goeman (2016)8Yekutieli (2008)

29 / 45

Page 34: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simulation: Results

False Filtered Discovery Rate Power

0.00 0.25 0.50 0.75 1.00 0.00 0.25 0.50 0.75 1.00

0.00

0.25

0.50

0.75

1.00

0.00

0.05

0.10

0.15

0.20

Signal Amplitude

Focused BH

BH

Focused BH (permutation)

Structured Holm

Focused BH (oracle)

Yekutieli

30 / 45

Page 35: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Application: UK Biobank PheWAS with outer nodes filter

HLA region on chromosome 6 is known to affect many diseases.

Conducted PheWAS analysis for the HLA-B*27:05 allele,studied previously by Cortes et al (Nature Genetics, 2017).

Computed p-values testing marginal association between this alleleand the m = 3265 ICD-10 codes that had at least 50 cases.9

BH, Structured Holm, Yekutieli, Focused BH appliedwith q = 0.05.

9This filtering step does not need to be corrected for, since it does not takethe response variable into account.

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Page 36: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Number of outer node rejections made by each method

Method Outer node rejections

BH 28Focused BH 24Structured Holm 13Yekutieli 1

32 / 45

Page 37: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focused BH rejects 34 nodes, 24 outer nodes

Circulat

ory

Neoplas

ms

Nervo

us

Ear Eye Respira

tory

Skin Pregn

ancy

Musc

uloske

letal

Clinica

l sym

ptom

s

Inju

ries

Key

Not rejected by Focused BH

Rejected by Focused BH

33 / 45

Page 38: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

FBH rejects 11 outer nodes more than Structured Holm

Circulat

ory

Neoplas

ms

Nervo

us

Ear Eye Respira

tory

Skin Pregn

ancy

Musc

uloske

letal

Clinica

l sym

ptom

s

Inju

ries

Key

Not rejected by Focused BH

Rejected by Focused BH

Outer node rejected by Focused BH but not Structured Holm

34 / 45

Page 39: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Summary of Focused BH

p-values Filtered rejections

Initial rejectionsBH Filter

Filter Focused BH

BH

Focused BH guarantees Type-I error control when data analysisinvolves automatic curation via a pre-specified filter.

Filtering framework is general; applies beyond examples presented.

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Page 40: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Part II: From automatic to manual curation

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Page 41: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 42: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 43: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 44: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 45: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 46: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Manually curating promising hypotheses

Consider the practice of re-running an FDR procedure withdifferent target levels until one obtains a “good” rejection set.

Rk = {H(1), . . . ,H(k)}: set corresponding to k smallest p-values.

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H

Simultaneous inference is one solution (e.g. Goeman and Solari2011, Berk et al 2013), but can be conservative.

37 / 45

Page 47: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simultaneous selective inferenceData scientist wants to inspect a “menu” of options

∅ = R0 ⊆ R1 ⊆ · · · ⊆ Rm ⊆ H.

Idea: provide corresponding upper bounds

FDP(Rk) =log(α−1)

log(1 + log(α−1))

1 + n · p(k)|Rk |

such that

Theorem (K. and Ramdas, AOS, in revision, 2019+)

Under independence of null p-values,

P[FDP(Rk) ≤ FDP(Rk) for all k] ≥ 1− α

for all n and all α ≤ 0.31.

Data scientist can freely choose from menu whilemaintaining validity of FDP bounds.

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Page 48: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simultaneous selective inference in a toy example

A

B C

0.0

0.2

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0.6

0.8

1.0

0 10 20 30 40 50

Hypothesis Index

Fals

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isco

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Pro

port

ion

Bou

nd

Simultaneous Selective Bound (KR19) Simultaneous Bound (GS11) True FDP

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Page 49: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Linear upper bounds for empirical processes

For bounds of the form FDP(t) =a + bt

R(t), we seek a, b such that

P[V (t) ≤ a + bt for all t ∈ [0, 1]] ≥ 1− α,where V (t) =

∑j∈H0

I (pj ≤ t).

Existing finite-sample bounds:10

I V (t) = 1αnt;

tight very near 0.

I V (t) =√

n2 log 1

α + nt;

tight near 1.

We obtain a new bound byexploiting connection betweenempirical and Poisson processes.

10Robbins (1954) and Dvoretsky Kiefer Wolfowitz (1956)40 / 45

Page 50: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Linear upper bounds for empirical processes

For bounds of the form FDP(t) =a + bt

R(t), we seek a, b such that

P[V (t) ≤ a + bt for all t ∈ [0, 1]] ≥ 1− α,where V (t) =

∑j∈H0

I (pj ≤ t).

Existing finite-sample bounds:10

I V (t) = 1αnt;

tight very near 0.

I V (t) =√

n2 log 1

α + nt;

tight near 1.

We obtain a new bound byexploiting connection betweenempirical and Poisson processes.

10Robbins (1954) and Dvoretsky Kiefer Wolfowitz (1956)40 / 45

Page 51: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Comparing to existing bounds (n = 500, α = 0.05)

1

100

10000

0.0001 (Bonferroni level) 0.05 (Nominal level) 1

t

Bou

nd o

n V

(t)

Bound Robbins KR DKW (Pointwise Quantile)

41 / 45

Page 52: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simultaneous selective inference with side information

KR19+ bounds can leverage side information to give datascientists a better menu of rejection sets to choose from.

I Hypotheses ordered a priori(same menu as accumulation test11)

I Hypotheses ordered adaptively(same menu as AdaPT or STAR12)

I Hypotheses ordered according to variable selection importance(same menu as knockoffs13)

11Li and Barber (2017)12Lei and Fithian (2018), Lei, Ramdas, Fithian (2019+)13Barber and Candes (2015)

42 / 45

Page 53: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simultaneous selective inference for knockoffs

Knockoffs method (Barber and Candes, 2015) developed forvariable selection with FDR control.

Knockoff statistics W1, . . . ,Wm assigned to variables instead ofp-values, ordering variables based on

W(1) ≥W(2) ≥ · · · ≥W(m).

BR19+ derived uniform FDP bounds for knockoffs as well:

FDP(Rk) =log( 1

α)

log(2− α)

1 + |{j : Wj ≤ −W(k)}||Rk |

.

Uniform bounds for knockoffs first considered byK. and Sabatti (AOAS, 2019).

43 / 45

Page 54: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Replicability guarantees for modern data analysis pipelines

Different modes of curation require different statistical approaches:

Mode of curation Statistical approach

1. Automatic (filtering) Focused BH2. Manual (exploration) Simultaneous selective inference

These lie on a spectrum from selective to simultaneous inference:

More flexibility, but more conservative guarantees.

Selective inference

Simultaneous inference

1 2

Less flexibility, but less conservative guarantees

Open questions:

I (Applications) Pairing applications with inferential guarantees;

I (Theory, Methodology) Filling in the spectrum withpowerful procedures using realistic assumptions.

44 / 45

Page 55: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Replicability guarantees for modern data analysis pipelines

Different modes of curation require different statistical approaches:

Mode of curation Statistical approach

1. Automatic (filtering) Focused BH2. Manual (exploration) Simultaneous selective inference

These lie on a spectrum from selective to simultaneous inference:

More flexibility, but more conservative guarantees.

Selective inference

Simultaneous inference

1 2

Less flexibility, but less conservative guarantees

Open questions:

I (Applications) Pairing applications with inferential guarantees;

I (Theory, Methodology) Filling in the spectrum withpowerful procedures using realistic assumptions.

44 / 45

Page 56: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Replicability guarantees for modern data analysis pipelines

Different modes of curation require different statistical approaches:

Mode of curation Statistical approach

1. Automatic (filtering) Focused BH2. Manual (exploration) Simultaneous selective inference

These lie on a spectrum from selective to simultaneous inference:

More flexibility, but more conservative guarantees.

Selective inference

Simultaneous inference

1 2

Less flexibility, but less conservative guarantees

Open questions:

I (Applications) Pairing applications with inferential guarantees;

I (Theory, Methodology) Filling in the spectrum withpowerful procedures using realistic assumptions.

44 / 45

Page 57: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Thank you.

All papers and code available athttp://web.stanford.edu/~ekatsevi/index.html.

45 / 45

Page 58: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

PRDS condition

Definition (Benjamini Yekutieli 2001)

The vector p is PRDS if for any null j and non-decreasing setD ⊆ [0, 1]m, the quantity P[p ∈ D|pi ≤ t] is nondecreasing int ∈ (0, 1].

1 / 13

Page 59: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Definition of power in the context of filtering

Maximum possible weighted number of non-null rejections is

Tmax ≡ maxR,p

∑j∈H1

Uj

; U = F(R,p),

Then, define power via

π(U) = E[∑

j∈H1Uj

Tmax

].

2 / 13

Page 60: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simulation 2: GWAS with clump filtering

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2

4

6

0 1000 2000 3000

Position

−lo

g(P

)

I Genome of length 3000, with 100 LD blocks of size 30

I Simulated genotype data with local correlations

I Phenotypes from linear model with 10 nonzero coefficients

I Univariate association p-values generated for each SNP

I For simplicity, filter uses a priori LD blocks as clumps

3 / 13

Page 61: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Simulation 2: Results

False Filtered Discovery Rate Power

0.00 0.25 0.50 0.75 1.00 0.00 0.25 0.50 0.75 1.00

0.00

0.25

0.50

0.75

1.00

0.1

0.2

0.3

Signal Amplitude

BH Focused BH Focused BH (permutation) Focused BH (oracle)

4 / 13

Page 62: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Robustness experiment

● ● ●

●●

0.06

0.08

0.10

0.00 0.25 0.50 0.75 1.00

Signal Amplitude

FD

R

Experiment ● ● ●Non−monotonic Non−monotonic and non−PRDS Non−PRDS

5 / 13

Page 63: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Outer nodes found by BH but not Focused BH

I Other and unspecified antidepressants [as a cause of death viacomplication of medical care]

I Urticaria [also known as hives]

I Localisation-related (focal) (partial) symptomatic epilepsy andepileptic syndromes with complex partial seizures

I Meniere’s disease

6 / 13

Page 64: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Outer nodes found by Focused BHbut not Structured Holm

I Symptoms, signs and abnormal clinical and laboratory findings

I Other benign neoplasms of connective and other soft tissues

I Meningitis, unspecified

I Other specified polyneuropathies

I Cardiomegaly

I Scrotal varices

I Chronic sinusitis

I Paralysis of vocal cords and larynx

I Cellulitis of other sites

I Rheumatoid arthritis, unspecified (Multiple sites)

I Other synovitis and tenosynovitis

7 / 13

Page 65: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

FBH rejects 4 nodes fewer than BH

Circulat

ory

Neoplas

ms

Nervo

us

Ear Eye Respira

tory

Skin Pregn

ancy

Musc

uloske

letal

Clinica

l sym

ptom

s

Inju

ries

Key

Not rejected by Focused BH

Rejected by Focused BH

Rejected by BH but not Focused BH

8 / 13

Page 66: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focusing on diseases of the musculoskeletal system

Diseases of the musculoskeletalsystem and connective tissue

Disorders ofsynovium and tendon

Synovitis andtenosynovitis

Other synovitisand tenosynovitis

Inflammatorypolyarthropathies

Other rheumatoidarthritis

Rheumatoid arthritis,unspecified

Rheumatoid arthritis,unspecified

(Multiple sites)

Rheumatoid arthritis,unspecified

(Shoulder region)

Rheumatoid arthritis,unspecified

(Hand)

Infectiousarthropathies Spondylopathies

Ankylosingspondylitis

Ankylosingspondylitis

(Site unspecified)

9 / 13

Page 67: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focusing on diseases of the skin

Diseases of the skin andsubcutaneous tissue

Infections of the skinand subcutaneous tissue

Cellulitis

Cellulitis ofother sites

Papulosquamousdisorders

Psoriasis

Arthropathicpsoriasis

Urticaria anderythema

Urticaria(Hives)

10 / 13

Page 68: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Soft outer nodes filter

0.75

0.33

0.75 0.5 1

0 1 1

1

8

a b g

a,b∗ b∗,e f,g g

a,b,c b,e,f,g i l m,n,o p,q,r,s,t

a,b,c,d

a,b,c,e,f,g,i,lm,n,o,p,q,r,s,t

11 / 13

Page 69: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Multi-filter Focused BH

Given M filters F1, . . . ,FM , suppose one wants R∗ such that

FDPFk= E[FDP(Fk(R∗,p))] ≤ qk for all k = 1, . . . ,m.

For a threshold t, we can construct FDPk(t) as in Focused BH,and then choose

t∗ = max{t ∈ {0, p1, . . . , pm} : FDPk(t) ≤ qk for all k}.

This will control FDR for all filtered rejection sets if p is PRDSand all filters are monotonic.

12 / 13

Page 70: Multiple testing for modern data: structure, curation, and replicability · 2021. 1. 6. · Genotype data have spatial structure Nearby SNPs are strongly correlated with each other.

Focused Storey BH

Writing

mλ0 =

1 + |{j : pj > λ}|1− λ

,

following Storey, we can define

FDPStorey(t) =mλ

0 · t|F(R(t,p),p)|

.

The corresponding procedure controls FDR under independence forsimple filters.

13 / 13


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