Ratio Scale

Instructions on how to install LabBench

Represents a continuous rating scale (e.g., Visual Analog Scale) where responses are given as a real-valued position along a defined length.

Availability:

context.Instruments.<RatioScaleName>

Properties

Name	Type	Description
`Length`	`float`	Total length of the scale. Defines the maximal possible rating value.

Methods

Name	Signature	Description
`GetCurrentRating`	`GetCurrentRating()` → `float`	Returns the current rating value on the scale.
`GetRatioRating`	`GetRatioRating()` → `float`	Returns the current rating value (same scale domain as `0` to `Length`).
`SetRatioRating`	`SetRatioRating(rating: float)` → `None`	Sets the current rating on the scale. Updates the device state.

Typical usage example

scale = context.Instruments.RatioScale

# Read current rating
rating = scale.GetCurrentRating()

# Set rating programmatically
scale.SetRatioRating(5.0)

# Access scale length
max_val = scale.Length

Notes / gotchas

Valid rating values are typically within [0, Length]; behavior outside this range is undefined.
Ratings are continuous (floating-point), unlike interval or ordinal scales.
SetRatioRating directly modifies the device state and may affect participant interaction.
GetCurrentRating and GetRatioRating return equivalent values.

Last modified May 21, 2026: Device server implementation (#1375) (5dd5648d)