Variables of LookInfo

Gabriel Potvin

October 16, 2025

The variables in LookInfo define the multiple looks design parameters. They can be used in custom scripts for the Analysis Integration Point and the Treatment Selection Integration Point. To access these parameters in your R code, use the syntax: LookInfo$NameOfTheVariable, replacing NameOfTheVariable with the appropriate parameter name.

The tables below describe each variable and notes any conditions under which it can or cannot be used in a project on East Horizon Explore and East Horizon Design. Availability notes are only specified when they differ from the default availability of the integration points (see the pages linked above for details).

LookInfo is only available for Statistical Design = Group Sequential.

For Study Objective = Two Arm Confirmatory

For Endpoint Type = Continuous, Binary, Time-to-Event, Continuous with Repeated Measures

Variable	Type	Description	Notes for Explore	Notes for Design
NumLooks	Integer	Number of looks.
CurrLookIndex	Integer	Current index look, starting from 1.
InfoFrac	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the information fraction for each look.
CumAlpha	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the cumulative alpha spent (for one-sided tests) for each look.		Only available if Test Type = One-sided.
CumAlphaLower	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the lower cumulative alpha spent (for two-sided tests) for each look. Same as CumAlpha if left-tailed one-sided test. Only makes sense to use for two-sided asymmetric tests.	Only available if Tail Type = Left-tailed. Two-sided tests do not exist, so this variable is not useful: use CumAlpha instead.	Only available if Test Type = One-sided and Tail Type = Left-tailed, or Test Type = Two-sided asymmetric or symmetric.
CumAlphaUpper	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the upper cumulative alpha spent (for two-sided tests) for each look. Same as CumAlpha if right-tailed one-sided test. Only makes sense to use for two-sided asymmetric tests.	Only available if Tail Type = Right-tailed. Two-sided tests do not exist, so this variable is not useful: use CumAlpha instead.	Only available if Test Type = One-sided and Tail Type = Right-tailed, or Test Type = Two-sided asymmetric or symmetric.
CumCompleters	Vector of Integer	Vector of length LookInfo$NumLooks, containing the cumulative number of completers for each look.	Not available for Endpoint Type = Time-to-Event and for Vaccine Efficacy (Endpoint Type = Binary with Lower Value and Test = 1 - Ratio of Proportions or 1 - Ratio of Poisson Rates).	Not available for Time-to-Event tests.
CumEvents	Integer	Cumulative events.	Only available for Endpoint Type = Time-to-Event and for Vaccine Efficacy (Endpoint Type = Binary with Lower Value and Test = 1 - Ratio of Proportions or 1 - Ratio of Poisson Rates).	Only available for Time-to-Event tests.
LookTime	Numeric	Look time on calendar scale.		Only available for Time-to-Event tests if Look Fix Option = Time-based.
RejType	Integer	Rejection type.	Possible values: – 0: One-sided efficacy upper. – 1: One-sided futility upper. – 2: One-sided efficacy lower. – 3: One-sided futility lower. – 4: One-sided efficacy upper, futility lower. – 5: One-sided efficacy lower, futility upper.	Possible values: – 0: One-sided efficacy upper. – 1: One-sided futility upper. – 2: One-sided efficacy lower. – 3: One-sided futility lower. – 4: One-sided efficacy upper, futility lower. – 5: One-sided efficacy lower, futility upper. – 6: Two-sided efficacy only. – 7: Two-sided futility only. – 8: Two-sided efficacy, futility. – 9: Equivalence.
EffBdryScale	Integer	Efficacy boundary scale.	Possible values: – 0: Z scale.	Possible values: – 0: Z scale. – 1: p-value scale.
EffBdry	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the efficacy boundary values (for one-sided tests) for each look.	Set to NA for Endpoint Type = Continuous with Repeated Measures.	Only available if Test Type = One-sided.
EffBdryLower	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the lower efficacy boundary values (for two-sided tests) for each look.	Only available if Tail Type = Left-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead.	Only available if Test Type = One-sided and Tail Type = Left-tailed, or Test Type = Two-sided asymmetric or symmetric.
EffBdryUpper	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the upper efficacy boundary values (for two-sided tests) for each look.	Only available if Tail Type = Right-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead.	Only available if Test Type = One-sided and Tail Type = Right-tailed, or Test Type = Two-sided asymmetric or symmetric.
FutBdryScale	Integer	Futility boundary scale.	Possible values: – 0: Z scale. – 2: Delta scale.	Possible values: – 0: Z scale. – 1: p-value scale. – 2: Delta scale. – 3: Conditional power scale.
CPDeltaOption	Delta option for conditional power computation: - 0: Design Delta. - 1: Estimated Delta.	Not available.	Only available if Futility Boundary Scale = Conditional Power.
FutBdry	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the futility boundary values (for one-sided tests) for each look.		Only available if Test Type = One-sided.
FutBdryLower	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the lower futility boundary values (for two-sided tests) for each look.	Only available if Tail Type = Left-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead.	Only available if Test Type = One-sided and Tail Type = Left-tailed, or Test Type = Two-sided asymmetric or symmetric.
FutBdryUpper	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the upper futility boundary values (for two-sided tests) for each look.	Only available if Tail Type = Right-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead.	Only available if Test Type = One-sided and Tail Type = Right-tailed, or Test Type = Two-sided asymmetric or symmetric.
BindingType	Integer	Binding type: - 0: Non-binding. - 1: Binding.
InterimVisit	Integer	Index of the visit which is driving the interims (starts at 1).	Only available for Endpoint Type = Continuous with Repeated Measures.	Not available.
FutContrast	Integer	The contrast based on which futility boundaries are being computed: – 0: Primary contrast. – 1: Secondary contrast.	Only available for Endpoint Type = Continuous with Repeated Measures.	Not available.
IncludePipeline	Integer	Indicates whether to include pipeline subjects in the interim: – 0: Do not include. – 1: Include.	Only available for Endpoint Type = Continuous with Repeated Measures.	Not available.

For Endpoint Type = Dual (TTE-TTE or TTE-Binary)

Named List of length equal to the number of endpoints, indicating the trial type for each endpoint. For example, TrialType[“Endpoint 1”] is the type for Endpoint 1.

Variable	Type	Description	Notes for Explore
NumEndpointLooks	Named List of Integer	Named List of length equal to the number of endpoints, indicating the number of looks for each endpoint. For example, NumEndpointLooks[“Endpoint 1”] is the number of looks for Endpoint 1.
NumLooks	Integer	Number of looks, defined as the maximum across all endpoints.
CurrLookIndex	Integer	Current index look, starting from 1.
SyncInterim	Integer	Interim synchronization option: - 1: Based on endpoint 1. - 2: Based on endpoint 2.
InputInfoFrac	Named List of Vector of Numeric	Named List of length equal to the number of endpoints, containing the information fraction vector for each endpoint. For example, InputInfoFrac[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the information fraction for each look for Endpoint 1.	For “Endpoint 1”, some initial entries will be NA if SyncInterim = 2. Some later entries will be NA if SyncInterim = 1 and NumEndpointLooks[“Endpoint 2”] > NumEndpointLooks[“Endpoint 1”].
CumCompleters	Named List of Vector of Integer	Named List of length equal to the number of endpoints, containing the cumulative number of completers vector for each endpoint. For example, CumCompleters[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the cumulative number of completers for each look for Endpoint 1.	Not available for Dual Endpoint = TTE-TTE. Set to NA for endpoints with Endpoint Type = Time-to-Event.
CumEvents	Named List of Vector of Integer	Named List of length equal to the number of endpoints, containing the cumulative events vector for each endpoint. For example, CumEvents[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the cumulative number of events for each look for Endpoint 1.	Set to NA for endpoints with Endpoint Type = Binary.
RejType	Named List of Integer	Named List of length equal to the number of endpoints, containing the rejection type for each endpoint. For example, RejType[“Endpoint 1”] is the rejection type for Endpoint 1. Possible values: – 0: One-sided efficacy upper. – 1: One-sided futility upper. – 2: One-sided efficacy lower. – 3: One-sided futility lower. – 4: One-sided efficacy upper, futility lower. – 5: One-sided efficacy lower, futility upper.
EffBdryScale	Named List of Integer	Named List of length equal to the number of endpoints, containing the efficacy boundary scale for each endpoint. For example, EffBdryScale[“Endpoint 1”] is the efficacy boundary scale for Endpoint 1. Possible values: – 0: Z scale.
EffBdry	Named List of Vector of Numeric	Named List of length equal to the number of endpoints, containing the efficacy boundary values for each endpoint. For example, EffBdry[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the efficacy boundary values for each look for Endpoint 1.	Set to NA if efficacy boundaries are skipped for some looks.
EffBdryLower	Vector of Numeric	Named List of length equal to the number of endpoints, containing the lower efficacy boundary values for each endpoint. For example, EffBdryLower[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the lower efficacy boundary values for each look for Endpoint 1.	Only available if Tail Type = Left-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead. Set to NA if efficacy boundaries are skipped for some looks.
EffBdryUpper	Vector of Numeric	Named List of length equal to the number of endpoints, containing the upper efficacy boundary values for each endpoint. For example, EffBdryUpper[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the upper efficacy boundary values for each look for Endpoint 1.	Only available if Tail Type = Right-tailed. Two-sided tests do not exist, so this variable is not useful: use EffBdry instead. Set to NA if efficacy boundaries are skipped for some looks.
FutBdryScale	Named List of Integer	Named List of length equal to the number of endpoints, containing the futility boundary scale for each endpoint. For example, FutBdryScale[“Endpoint 1”] is the futility boundary scale for Endpoint 1. Possible values: – 0: Z scale. – 2: Delta scale - 6: Hazard ratio scale.
FutBdry	Named List of Vector of Numeric	Named List of length equal to the number of endpoints, containing the futility boundary values for each endpoint. For example, FutBdry[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the futility boundary values for each look for Endpoint 1.	Set to NA if futility boundaries are skipped for some looks.
FutBdryLower	Vector of Numeric	Named List of length equal to the number of endpoints, containing the lower futility boundary values for each endpoint. For example, FutBdryLower[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the lower futility boundary values for each look for Endpoint 1.	Only available if Tail Type = Left-tailed. Two-sided tests do not exist, so this variable is not useful: use FutBdry instead. Set to NA if futility boundaries are skipped for some looks.
FutBdryUpper	Vector of Numeric	Named List of length equal to the number of endpoints, containing the upper futility boundary values for each endpoint. For example, FutBdryUpper[“Endpoint 1”] is a vector of length LookInfo$NumLooks containing the upper futility boundary values for each look for Endpoint 1.	Only available if Tail Type = Right-tailed. Two-sided tests do not exist, so this variable is not useful: use FutBdry instead. Set to NA if futility boundaries are skipped for some looks.
BindingType	Named List of Integer	Named List of length equal to the number of endpoints, containing the binding type for each endpoint. For example, BindingType[“Endpoint 1”] is the binding type for Endpoint 1. Possible values: - 0: Non-binding. - 1: Binding.

Notes:

• Dual endpoints are not available for East Horizon: Design.
• “Endpoint 1” is used as a sample endpoint name. It will be the actual endpoint name as specified by the user.

For Study Objective = Multiple Arm Confirmatory or Dose Finding

Variable	Type	Description	Notes for Explore	Notes for Design
NumLooks	Integer	Number of looks.
CurrLookIndex	Integer	Current index look, starting from 1.
InfoFrac	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the information fraction for each look.
CumAlpha	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the cumulative alpha spent (for one-sided tests) for each look.		Only available if Test Type = One-sided.
CumCompleters	Vector of Integer	Vector of length LookInfo$NumLooks, containing the cumulative number of completers for each look.	Not available for Endpoint Type = Time-to-Event.	Not available for Time-to-Event tests.
CumEvents	Vector of Integer	Vector of length LookInfo$NumLooks,containing the cumulative event for each look.	Only available for Endpoint Type = Time-to-Event. Not available for Study Objective = Dose Finding.	Only available for Time-to-Event tests.
RejType	Integer	Rejection type: – 0: One-sided efficacy upper. – 1: One-sided futility upper. – 2: One-sided efficacy lower. – 3: One-sided futility lower. – 4: One-sided efficacy upper, futility lower. – 5: One-sided efficacy lower, futility upper.
EffBdryScale	Integer	Efficacy boundary scale.	Not available for Study Objective = Dose Finding. Possible values: – 0: Z scale.	Possible values: 1: Adjusted p-value scale.
EffBdry	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the efficacy boundary values for each look.	Not available for Study Objective = Dose Finding.
FutBdryScale	Integer	Futility boundary scale.	Possible values: – 2: Delta scale. – 6: Hazard ratio scale.	Possible values: – 1: Adjusted p-value scale. – 2: Delta scale. – 6: Hazard ratio scale.
FutBdry	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the futility boundary values for each look.
PoCScale	Integer	Proof of concept (PoC) scale: - 0: High dose vs. control.	Only available for Study Objective = Dose Finding.	Not available.
PoCThreshold	Vector of Numeric	Vector of length LookInfo$NumLooks, containing the proof of concept (PoC) threshold.	Only available for Study Objective = Dose Finding.	Not available.