Human judgment calls made throughout the data science life cycle can change the conclusions drawn from data. Independent analysts often make different choices when given the same data, leading to often unacceptable variations in results and contributing to the ongoing reproducibility crisis across scientific disciplines. The rapid adoption of agentic tools threatens to amplify this crisis. Several approaches have been developed to address this variation by following the same strategy: repeating an analysis under different combinations of analytical decisions and inspecting the distribution of outcomes. Examples include multiverse analysis, specification curve analysis, and vibration of effects. More broadly, the Predictability-Computability-Stability (PCS) framework assesses how documented judgment calls across the data science life cycle affect conclusions, with predictability serving as a reality-check that a model captures signal. Each of these approaches results in a "multiverse" object. While the distribution of outcomes reflects the overall variability of conclusions, estimating the influence of each individual decision requires additional tools. A common heuristic is to train a model to predict the outcome from these decisions and treat its coefficients or feature importances as proxies for each decision's influence. Although this strategy may work in certain cases, it assumes the model is correctly specified and accurately predicts the outcome, which we show is not always the case. In this work, we introduce DECIDE, a model-free framework that quantifies each decision's importance from the actual outcomes across the plausible decision space, avoiding issues of predictability by design. We demonstrate the effectiveness of DECIDE by applying it to real-world multiverse analyses. We further provide what is, to our knowledge, the first formal definition of the multiverse.
Figures & tables
Figure 1: A simple multiverse represented as a depth-3 tree, with each leaf node holding the result f(U) of one universe. Here, we can imagine c1 being data cleaning (e.g., drop or impute missing values), c2 being feature selection (e.g., include or exclude sensitive attributes), and c3 being model choice (e.g., logistic regression or random forest). Taking c2 as the decision of interest , each leaf node color marks one comparable set: the universes which agree on every decision but c2 . Decide measures the spread Φ within each of these sets.
Figure 2: Surrogate regression models poorly approximate the multiverse outcomes they are used to explain. Left: observed vs. predicted distributions of universe outcomes. Right: residuals vs. fitted values. Top: on fertility , the predicted distribution has a different shape than the observed outcomes. Bottom: on hurricane , the surrogate misses the long right tail of observed outcomes and the residuals show heteroscedasticity, outliers, and curvature.
Figure 3: Full tree view of the Fertility / Durante multiverse. Its branch structure expands over its five decisions, making explicit the full set of possible universe paths.
Figure 4: A multiverse consisting of three binary decisions. The first two levels ( c1 and c2 ) impact the output accuracies through their interaction. The last level ( c3 ) influences the accuracies with its fixed effect.
fANOVA
Random Forest
\textscDecidetotal
Reg.
Main
Total
MDI
PFI
c1
0.000625
0.000000
0.106792
0.355601
0.294151
0.000544
c2
0.000625
0.000000
0.116994
0.354927
0.283771
0.000534
c3
0.000400
0.040000
0.479171
0.627509
0.422078
0.000727
Table 1: Comparison of decision importance scores on the multiverse shown in Figure 4 . Only \textscDecidetotal correctly identifies that the interacting decisions ( c1,c2 ) have a higher importance than the main effect decision ( c3 ). The most important feature(s) for each approach are shown in bold.
Decide
fANOVA
Decision
Total
Main
Ratio
Total
Main
Reg.
Relationship Status
0.089
0.078
88.3%
0.506
0.410
0.297
Fertile
0.087
0.056
64.0%
0.417
0.251
0.244
Menstrual Calculation
0.041
0.011
27.1%
0.193
0.055
0.152
Cycle Length
0.028
0.012
43.7%
0.132
0.050
0.152
Certainty
0.008
0.005
69.6%
0.054
0.022
0.146
Table 2: Importance estimates per decision, by method for the Fertility / Durante multiverse [ 52 , 11 ] .
Figure 5: Ablation stability on the Fertility / Durante multiverse. Left: all pairs agree closely on the full multiverse ( ρ≥0.90 ); after ablation, disagreement is concentrated in pairs including regression as an estimator. Right: \textscDecidetotal is the most stable estimator overall and most stable or tied for most stable in every ablation, regression is the least.
Figure 6: Ablation stability on the Hurricane / Jung multiverse. Left: agreement splits along total vs. main effects: the two total-effect estimators agree almost perfectly with each other, as do the two main-effect estimators, while pairs across the two groups agree less, most visibly on the full multiverse. Right: \textscDecidetotal and fANOVAtotal are the most stable on average; fixing ‘Model’ destabilizes all other estimators.
Decide
fANOVA
Decision
Total
Main
Ratio
Total
Main
Reg.
Model
2.251
1.004
44.6%
0.540
0.247
2.004
Death Outliers
1.714
0.722
42.1%
0.427
0.175
1.006
Damage Transform
1.035
0.001
0.1%
0.231
0.000
0.059
Damage Outliers
0.964
0.157
16.3%
0.229
0.041
0.336
Covariates
0.771
0.057
7.4%
0.186
0.013
0.383
Table 3: Importance estimates per decision, by method for the Hurricane / Jung multiverse [ 12 , 53 ] .
Table 4: Importance estimates per decision, by method for the three multiverses in Orben & Przybylski [ 59 ] .
Decide
fANOVA
Multiverse
NM
Reg.
Main + Total
Main
Total
Fertility / Durante
210
11 ms
144 ms
132 ms
345 ms
Hurricane / Jung
1,728
6 ms
220 ms
189 ms
7.3 s
YRBS
372
5 ms
91 ms
119 ms
3.2 s
MTF
40,966
49 ms
766 ms
4.4 s
–
MCS
20,004
84 ms
181 ms
13.9 s
–
Table 5: Median execution time per method and multiverse, over 3 runs. NM denotes the size of the multiverse. Dashes mark methods not evaluated for a given multiverse due to computational constraints. Decide includes several checks regarding data structure in its timing.
Λ= Mean, Φ= Variance
Λ= Max, Φ= Range
Decision
Group
\textscDecidetotal
Rank
\textscDecidetotal
Rank
c1
Routine
0.000900
1
0.060
8
c2
Routine
0.000784
2
0.056
9
c3
Routine
0.000676
3
0.052
10
c4
Routine
0.000576
4
0.048
11
c5
Routine
0.000484
5
0.044
12
Table 6: Decide importance scores on the synthetic multiverse. The catastrophic decision c12 ranks last under average-case instantiation but first under worst-case instantiation.
Appendix figures & tables7 assets
Supplementary material from the paper’s appendix.
Appendix
Figure B1: Visualizations of the three types of sparsity described in Section 3.6 . The decision of interest is denoted in orange . Colored arcs represent comparable sets.
Figure B2: Method stability for the three adolescent well-being multiverses of Orben and Przybylski [ 59 ] . Top: inter- and intra-method stability under ablation for YRBS. Bottom: inter-method agreement on the full multiverse for MTF and MCS, which vary only three decisions and are therefore not ablated. YRBS: every estimator stays highly stable; the most difficult ablation is fixing ‘X Variable’, where the main-effect estimators drop. MTF: Decide and fANOVA agree closely ( 0.93 – 1.00 ), while regression is only weakly correlated with either ( 0.14 – 0.49 ). MCS: methods disagree strongly; regression is almost perfectly anti-correlated with \textscDecidemain ( −0.96 ) and fANOVAmain ( −0.92 ). Note that all three multiverses vary at most four judgment calls, so the individual cells are coarse (see the caveat in Section 5.4 ).
Decision
Description
No. of Opts.
Fertile
Assessment of fertility (high/low) using different windows as cutoffs
5
Menstrual Calculation
How the next menstrual onset is estimated
3
Relationship Status
How relationship status is coded, in particular the option “dating or involved with only one partner”
3
Cycle Length
Exclusion criteria for women based on cycle length
3
Certainty
Exclusion criteria for women based on certainty of start days of previous menstrual onsets
2
Appendix
Table C1: Decisions in the Fertility / Durante multiverse. These five decisions lead to nfert=210 universes (less than the theoretical Nfert=270 universes due to constraints).
Decision
Description
No. of Opts.
Death Outliers
Whether to exclude the storms with the most deaths
3
Damage Outliers
Whether to exclude the storms with the most property damage
4
Femininity
Whether the ‘femininity’ of the hurricane name is encoded as continuous or binary
2
Model
Which model class to use.
2
Damage Transform
Whether to log-transform damage (i.e., measure with dollars or log-dollars)
2
Predictor Specification
Whether the effect of ‘femininity’ interacted with other features (and if so, which ones)
6
Appendix
Table C2: Decisions in the Hurricane / Jung multiverse. These seven decisions lead to Nhurr=1,728 universes.
Decision
Description
No. of Opts.
X Variable
Operationalization of technology use
3
Y Variable
Operationalization of well-being
31
Controls
Which covariates to include
2
Combination
How well-being measures are combined
2
Appendix
Table C3: Decisions in the YRBS multiverse. These four decisions lead to Nyrbs=372 universes.
Decision
Description
No. of Opts.
X Variable
Operationalization of technology use
13
Y Variable
Operationalization of well-being
4,095
Controls
Which covariates to include
2
Appendix
Table C4: Decisions in the MTF multiverse. These three decisions lead to NMTF=40,966 universes.
Decision
Description
No. of Opts.
X Variable
Operationalization of technology use
6
Y Variable
Operationalization of well-being
1,667
Controls
Which covariates to include
2
Respondent
Whether to use well-being measures by cohort members or caregivers
2
Appendix
Table C5: Decisions in the MCS multiverse. These four decisions lead to NMCS=20,004 universes. The authors selected and analyzed a subset of nMCS=20,004 universes out of a theoretical total of NMCS=603,979,752 defensible universes (or >2.5 trillion if any combination of covariates were to be explored). ‘Respondent’ is determined completely by ‘Y Variable’, and is thus merged in accordance with the strategy described in Section 3.6 .