I85PREP
⌘ K
EPSO AST/SC study materials
EPSO AST/SC study resources

EPSO AST/SC: Abstract Reasoning: Testing Rules Systematically

EPSO AST/SC · Work through your exam, one topic at a time.

All guide sections

Abstract Reasoning: Testing Rules Systematically

Abstract reasoning measures fluid intelligence: your ability to infer a rule from figures alone and apply it. EPSO AST/SC items include series (what comes next), analogies (A is to B as C is to ?), matrices (a missing cell in a grid) and odd-one-out sets. No language or mathematical knowledge is needed, but you must test rules systematically rather than by intuition.

Rule families to check

  • Count: sides, dots, lines, enclosed regions, intersections.
  • Position: movement clockwise, along rows, or alternating corners.
  • Orientation: rotation by 45 or 90 degrees, reflection (mirror), inversion.
  • Fill: shaded/unshaded alternation, colour change, size change.
  • Combination: superimpose, add, subtract, keep common elements.
  • Alternation: odd and even positions follow separate rules.

Method

Track one attribute at a time across every given figure. Write down counts or positions. Check whether the series splits into two interleaved sequences. Form a rule only when it explains every figure, then predict the answer before looking at the options.

Worked example

A series is described by its figures: figure 1 is a three-sided shape containing one dot; figure 2 a four-sided shape with two dots; figure 3 a five-sided shape with three dots; figure 4 a six-sided shape with four dots. Shading alternates, starting shaded in figure 1. Which figure comes next? Sides rise by one (3, 4, 5, 6, so 7). Dots rise by one (1, 2, 3, 4, so 5). Shading alternates shaded/unshaded, so figure 4 is shaded and figure 5 is unshaded. Answer: a seven-sided unshaded shape with five dots. A distractor with seven sides and four dots satisfies the shape rule but not the dot rule.

Traps that cost marks

  • Assuming rotation when the change is a reflection.
  • Finding a rule that fits the first three figures but fails the fourth.
  • Ignoring a second attribute because one rule already seems to work.
  • Choosing an option that matches the last figure rather than the next one.
  • Overcounting lines that touch or overlap.