Why Percentile Ranks Tell You More Than Raw Scores

Relying on clinical judgment alone is like detecting a fever by hand. Measurement-Based Care delivers better therapy outcomes.

In this clinical masterclass, Dr Ben Buchanan (Clinical Psychologist and NovoPsych Founder) and Dr David Hegarty (Head of Psychometrics) explore the transition from intuition-based practice to Measurement-Based Care (MBC). Drawing a parallel to the history of thermometry in medicine, Dr Buchanan notes that while clinicians once relied on “the hand on the forehead” to detect fever, modern practice demands the precision of a “measuring stick” to provide better therapy outcomes for mental health clinicians and their clients.

Timeline of the history of thermometers in medicine, from Hippocrates teaching students to detect fever by hand in 400BC, through the convenient thermometer of 1867 and Wunderlich's 100,000-observation research in 1868, to infrared thermometers in the 2000s — The history of thermometers in medicine — objective measurement took centuries to displace subjective judgement (Dr Ben Buchanan, Beyond the Scores masterclass).

Routine outcome monitoring improves treatment response with an effect size of d = .55.

What is Measurement-Based Care (MBC)?

Measurement-Based Care (MBC)—also referred to as Routine Outcome Monitoring (ROM), Feedback-Informed Treatment (FIT), or Psychotherapy Progress Monitoring—is defined as the systematic use of psychological assessments to drive clinical decision-making at the individual client level. Rather than relying solely on clinical judgment, MBC integrates psychometrics into the start, middle, and end of treatment to aid in clinical formulation and assessment.

NovoPsych offers a comprehensive suite of over 150 validated psychological scales for a wide variety of mental health-related presentations. Results from each completed assessment are presented with statistical data, useful graphs, and interpretive text. NovoPsych prioritises percentile ranks in psychometrics over raw scores, as they offer a more intuitive comparison against the general population; for instance, a score above the 90th percentile indicates a client is struggling significantly compared to 90% of the community.

A doctor who has devoted years of education and training to acquiring and refining a particular skill will inevitably be reluctant to accept a new development that seems to make all that effort redundant.

Paul Taylor, From Patient Data to Medical Knowledge

The masterclass Beyond the Scores: Using Psychometric Assessments for Better Outcomes, presented by Dr Ben Buchanan (Clinical Psychologist and NovoPsych Founder) and Dr David Hegarty (Head of Psychometrics), demonstrates how to embed Measurement-Based Care in everyday practice—from selecting the right scales to interpreting percentile ranks and sharing outcome graphs with clients and GPs. Watch the 45-minute recording for worked examples inside NovoPsych.

Treatment response tracking with NovoPsych

The masterclass demonstrated how specific assessments available on NovoPsych facilitate treatment response tracking. It included examples such as:

DASS-21 (Depression Anxiety Stress Scales): A broad-spectrum measure that can be administered quickly and regularly to monitor treatment progress.
CORE-10 (Clinical Outcomes in Routine Evaluation): Uses the Reliable Change Index (RCI) to determine statistical significance of changes in common psychological distress symptoms over time.
PCL-5 (PTSD Checklist for DSM-5): Allows for subscale analysis, helping clinicians identify specific targets associated with traumatic presentations (such as re-experiencing, avoidance, negative alterations in cognition and mood, and hyperarousal).

Example NovoPsych DASS-21 results table with raw scores, percentiles and severity descriptors, alongside a bar chart of DASS-21 percentiles for total distress, depression, anxiety and stress — NovoPsych DASS-21 results — percentile ranks give a more intuitive comparison against the general population than raw scores.

Evidence-Based Mental Health Practice

The case for MBC is supported by robust data and is a key aspect of Evidence-Based Mental Health Practice. Meta-analyses (e.g., Tam & Ronan, 2017) demonstrate that routine monitoring improves treatment response with an effect size of d=.55. Furthermore, MBC is highly effective in reducing treatment dropout statistics by fostering a shared conceptualisation and increasing client engagement through tangible visual data.

Having objective data is also a critical tool for reflective practice. By using insights provided by MBC, clinicians can pivot their approach or seek targeted supervision when they receive information that confirms a client’s deterioration or disengagement from treatment. Being a mental health clinician is a demanding job, and when routine outcome monitoring indicates treatment success with improved client outcomes, it can be validating and rewarding for a clinician.

Better patient experience and faster reporting

Modern software allows for seamless integration of MBC into clinical workflows via in-session iPad administration, QR codes in waiting rooms, or automated remote scheduling. For external reporting, interpretive text and graphical representations can be directly integrated into GP referral letters with outcome data. GPs report high satisfaction with these visual representations, which clearly illustrate the impact of interventions such as medication or specialised therapy.

Ultimately, moving beyond raw scores allows clinicians to validate the “invisible” experiences of their clients, turning intangible distress into a measurable path toward recovery.

View over 150 of the current psychometric tools available on NovoPsych here.

Warm regards,
Dr Ben Buchanan
Psychologist
NovoPsych Co-founder
[email protected]
LinkedIn

Dr David Hegarty