What Is CO-PO Mapping? NBA Course Articulation Explained
· By Edhitch Research Team
CO-PO mapping is the process of correlating each Course Outcome (CO) of a subject with the Program Outcomes (PO) it contributes to. Each correlation is scored on a scale of 1 to 3 — 1 for slight, 2 for moderate, 3 for substantial — and the completed grid is called the Course Articulation Matrix. CO-PO mapping is a mandatory part of NBA's Outcome-Based Education framework, because it is what links course-level teaching to program-level graduate attributes.
What CO-PO mapping is
CO-PO mapping is the structural link at the heart of Outcome-Based Education (OBE) — the framework on which all NBA accreditation is based.
The idea is straightforward. A degree programme has broad Program Outcomes — the attributes every graduate should have. But those attributes are not taught directly; they are built up, course by course, through dozens of individual subjects. CO-PO mapping is how an institution demonstrates that connection: it shows, for every course, which Program Outcomes that course contributes to, and how strongly.
Without mapping, OBE would be a claim with no evidence. With it, an institution can trace a clear line from a single classroom assessment all the way up to a program-level graduate attribute — and that traceability is exactly what NBA assessors look for.
CO and PO: the two terms
To understand the mapping, you need the two things being mapped:
- CO — Course Outcome. A statement of what a student should be able to do at the end of a single course. COs are written by the course faculty using action verbs from Bloom's Taxonomy (such as analyse, design, evaluate). A course typically has 4 to 8 COs.
- PO — Program Outcome. A graduate attribute defined by NBA, common to all engineering programmes. Under the current GAPC v4.0 framework, NBA defines 11 Program Outcomes — from Engineering Knowledge to Life-Long Learning.
Many courses also map to PSOs (Programme Specific Outcomes) — outcomes each programme writes for its own discipline. CO-PSO mapping works the same way as CO-PO mapping, on the same 1-to-3 scale.
Want the full list of Program Outcomes? See our reference guide to the 11 NBA Program Outcomes under GAPC v4.0 — including how the framework changed from 12 POs to 11.
The 1-2-3 correlation scale
CO-PO mapping is not a simple yes/no. For each Course Outcome, against each Program Outcome, the institution records how strongly they are related, using a three-point scale:
| Value | Strength | Meaning |
|---|---|---|
| 3 | Substantial (High) | The course outcome contributes strongly to that program outcome |
| 2 | Moderate (Medium) | The course outcome contributes moderately to that program outcome |
| 1 | Slight (Low) | The course outcome contributes only slightly to that program outcome |
| – | No correlation | A dash or blank cell — the two are not meaningfully related |
Source: NBA Outcome-Based Education manuals. The 1/2/3 correlation scale is standard across NBA SAR documentation.
The key discipline: not every CO should map to every PO. A common mistake is filling the matrix with high values everywhere, which signals weak, unjustified mapping. A genuine matrix has a realistic spread — many blanks, some 1s, and 3s reserved for outcomes that truly drive that PO.
The Course Articulation Matrix (with example)
When you record every CO against every PO, the result is a grid called the Course Articulation Matrix. Rows are the course's COs; columns are the POs (and PSOs); each cell holds the correlation value.
Here is a simplified example for a single course with five COs (showing the first six POs):
| CO | PO1 | PO2 | PO3 | PO4 | PO5 | PO6 |
|---|---|---|---|---|---|---|
| CO1 | 3 | 2 | – | – | 1 | – |
| CO2 | 2 | 3 | 2 | – | – | – |
| CO3 | 3 | 2 | 3 | 1 | – | – |
| CO4 | 2 | – | 2 | 3 | 1 | – |
| CO5 | 1 | – | – | 2 | 3 | 2 |
Illustrative example only. Green = 3 (substantial), amber = 2 (moderate), red = 1 (slight), dash = no correlation. A real matrix covers all 11 POs plus the programme's PSOs.
The same idea scaled up — mapping whole courses to POs across the full programme — produces the Programme Articulation Matrix. Together, these matrices are what NBA's SAR Criterion on outcomes requires institutions to present.
How CO-PO mapping is done
Mapping a course follows a consistent process:
Write clear Course Outcomes
The faculty member writes 4 to 8 COs for the course, each using a Bloom's Taxonomy action verb so the cognitive level is unambiguous. Weak COs make every later step unreliable.
Identify keywords in each CO and PO
For each CO, identify the key concepts and skills it addresses. Compare them with the wording of each Program Outcome to judge whether a genuine relationship exists.
Assign the correlation value
Where a CO relates strongly to a PO, assign 3; moderately, 2; slightly, 1; and where there is no real link, leave it blank or mark a dash. Judge each cell on its merits — do not default to high values.
Justify the mapping
Each non-blank cell should have a one- or two-line justification, using words drawn from the CO, the PO, and the course syllabus. Justification is what separates a defensible matrix from a guessed one.
Review and finalise
A committee of senior faculty reviews the COs and the mapping before they are finalised, checking for consistency and realistic distribution across the matrix.
How mapping feeds PO attainment
CO-PO mapping is not an end in itself — it is the mechanism that makes PO attainment calculable.
Once a course's CO attainment is measured from assessments (tests, labs, projects, the end-semester exam), each CO's attainment is carried up to the Program Outcomes it maps to — weighted by the correlation value. A CO connected to a PO with a strength-3 mapping contributes far more to that PO's attainment than one connected with a strength-1 mapping.
Aggregated across all the courses in a programme, these weighted contributions produce the program-level PO attainment. That figure is then typically split into a direct component (from assessments) and an indirect component (from student and stakeholder surveys), and combined into the final PO attainment NBA expects to see in the SAR.
In short: the correlation values you place in the matrix are not decorative — they are the weights in the attainment calculation. That is why a careless matrix produces misleading attainment numbers, and why NBA assessors scrutinise both.
Calculating CO-PO attainment by hand? Manual mapping and attainment calculation consume hundreds of faculty hours per cycle and introduce inconsistencies. Edhitch's CO-PO Attainment & Mapping Software automates the matrix and the attainment computation, with a per-faculty edition via CO-PO Pro.
Why CO-PO mapping matters for NBA
CO-PO mapping is mandatory under NBA's Outcome-Based Education framework. NBA accredits programmes that demonstrate OBE, and the SAR explicitly requires institutions to present CO-PO mapping — at minimum for the core courses of the programme.
Three reasons it carries weight beyond being a checkbox:
- It is the evidence of OBE. Mapping is how an institution proves teaching is organised around outcomes, not just content delivery.
- It drives the attainment numbers. Because PO attainment is computed using the mapping weights, the matrix directly shapes one of the most heavily scrutinised parts of the SAR.
- It must be defensible. NBA assessors test whether the mapping is justified. A matrix full of unjustified 3s is a recognised red flag and invites questions during the visit.
Done well, CO-PO mapping turns OBE from paperwork into a genuine, traceable account of how a programme builds its graduates' competence — which is exactly what accreditation is meant to verify.
Frequently asked questions
What is CO-PO mapping?
CO-PO mapping is the process of correlating each Course Outcome of a subject with the Program Outcomes and Programme Specific Outcomes it contributes to. Each correlation is scored 1 to 3, and the completed grid is the Course Articulation Matrix. It is a mandatory part of NBA's Outcome-Based Education framework.
What do 1, 2, and 3 mean in CO-PO mapping?
The correlation strength is scored as 1, 2, or 3. A value of 1 means slight (low) correlation, 2 means moderate (medium), and 3 means substantial (high). A dash or blank cell means there is no meaningful correlation between that Course Outcome and that Program Outcome.
What is a Course Articulation Matrix?
It is the grid that records the CO-PO mapping for a single course. Rows are the course's Course Outcomes, columns are the Program Outcomes and PSOs, and each cell holds the correlation value. The program-level version, mapping whole courses to POs, is the Programme Articulation Matrix.
Why is CO-PO mapping important in NBA accreditation?
It is the structural link in NBA's Outcome-Based Education model, connecting course-level teaching to program-level graduate attributes. Without mapping, PO attainment cannot be calculated, since PO attainment is derived from Course Outcome attainment weighted by the CO-PO correlation values. NBA's SAR explicitly requires it.
How is CO-PO mapping used to calculate PO attainment?
Once Course Outcome attainment is measured, each CO's attainment is carried to the POs it maps to, weighted by the correlation value. A strength-3 mapping contributes more than a strength-1 mapping. The weighted contributions across all courses combine into program-level PO attainment, which is split into direct and indirect components.
What is the difference between CO-PO and CO-PSO mapping?
CO-PO mapping correlates Course Outcomes with the standardised Program Outcomes defined by NBA, common to all engineering programmes. CO-PSO mapping correlates the same Course Outcomes with the Programme Specific Outcomes each programme writes for its own discipline. Both use the same 1 to 3 scale.
Official sources
- National Board of Accreditation (NBA) — Official Portal
- NBA SAR formats & Outcome-Based Education documents
The CO-PO mapping concept and the 1-2-3 correlation scale are summarised from NBA's Outcome-Based Education framework and SAR documentation. For exact requirements, refer to the official NBA SAR for your programme type. Last reviewed: May 18, 2026.