Should Health Numeracy Be Assessed Objectively or Subjectively?

Area of Science:

• Health decision-making research
• Psychometrics
• Medical informatics

Background:

• Numeracy influences decision-making, making it crucial for evaluating medical decision support interventions.
• Existing subjective and objective numeracy assessments vary in scope and ease of use.
• Optimal methods for assessing numeracy in medical decision-making research remain unclear.

Purpose of the Study:

• To compare subjective numeracy scales with objective numeracy scales.
• To assess the user acceptability and willingness to repeat assessments.
• To inform the best practices for numeracy assessment in medical decision research.

Main Methods:

• Internet surveys were used to compare the Subjective Numeracy Scale (SNS) with five objective numeracy scales.
• Participants completed one subjective and one objective numeracy assessment.
• User acceptability and willingness to repeat assessments were recorded.

Main Results:

• A total of 673 participants completed the surveys with a 78% response rate.
• Correlations between SNS and objective measures ranged from 0.19 to 0.44, indicating related but distinct constructs.
• The SNS and one objective scale (Numeracy Understanding in Medicine Instrument short form) showed similar acceptability; other objective scales were less acceptable.

Conclusions:

• Objective and subjective numeracy scales capture different aspects of numeracy.
• Further research is needed to determine which numeracy construct best predicts decision support intervention effectiveness.
• Measuring both objective and subjective numeracy is recommended to account for perceived and actual skills in medical decision-making research.