ScrollTest: Evaluating Scrolling Speed and Accuracy

TL;DR

ScrollTest is a versatile tool for objectively measuring scrolling speed and accuracy across various techniques and conditions, addressing limitations of previous models that intertwined scrolling with content selection.

Contribution

The paper introduces ScrollTest, a novel evaluation method that isolates scrolling performance without content selection, and provides comprehensive analysis across multiple devices and conditions.

Findings

Flicking and two-finger scrolling are the fastest techniques.

Flicking is relatively precise for onscreen targets.

Pressing arrow buttons yields the highest accuracy for nearby targets.

Abstract

Scrolling is an essential interaction technique enabling users to display previously off-screen content. Existing evaluation models for scrolling are often entangled with the selection of content, e.g., when scrolling on the phone for reading. Furthermore, some evaluation models overlook whether the user knows the target position. We have developed ScrollTest, a general-purpose evaluation tool for scrolling speed and accuracy that avoids the need for selection. We tested it across four dimensions: 11 different scrolling techniques/devices, 5 frame heights, 13 scrolling distances, and 2 scrolling conditions (i.e., with or without knowing the target position). The results show that flicking and two-finger scrolling are the fastest; flicking is also relatively precise for scrolling to targets already onscreen, but pressing arrow buttons on the scrollbar is the most accurate for scrolling to nearby targets. Mathematical models of scrolling are highly linear when the target position is unknown but like Fitts' law when known.