IIP vs. PMI: Which Shows Manufacturing Health Better?

You read about IIP and PMI in the same breath every month and assume they show the same thing. They do not. Both are economic indicators explained in business news as proxies for manufacturing health, but they measure different layers and react at different speeds. Picking the right one for your decision changes the answer.

This compares IIP and PMI head to head, shows when each is more useful, and gives a verdict on which one shows manufacturing health better.

Quick verdict first

PMI is the better leading indicator. It moves before official data does. IIP is the better lagging indicator. It confirms what already happened with hard volume numbers.

If you are deciding what is happening right now, watch PMI. If you are checking what actually happened last quarter, watch IIP.

What IIP actually measures

IIP stands for Index of Industrial Production. It tracks the change in physical output of about 800 product categories across mining, manufacturing, and electricity. The Ministry of Statistics and Programme Implementation publishes it monthly, with a six-week lag.

It is a quantity index. The numbers come from factory returns reported by registered units. If 100 cars rolled off the line in 2011-12 (the base year) and 130 cars rolled off this month, IIP shows 130.

What PMI actually measures

PMI stands for Purchasing Managers' Index. It is built from monthly surveys of purchasing managers across 500-plus companies. The respondents answer five questions: new orders, output, employment, supplier delivery times, and inventories.

The result is a single number. Above 50 means expansion compared to last month, below 50 means contraction. S&P Global compiles the Indian PMI and releases it on the first working day of every month for the previous month.

Side-by-side comparison

Why PMI moves first

Purchasing managers see new orders before factories produce them. They see input cost pressure before invoices arrive. They see hiring slowdowns before payroll changes. The PMI captures these signals in real time, while IIP only catches the actual output one or two months later.

If PMI dips below 50 for two consecutive months, IIP almost always shows weak prints in the next quarter. The lead is real and tradable.

Why IIP is more authoritative

IIP is built from physical production data submitted by factories. It is not a sentiment survey. When the RBI or central government writes its policy statements, IIP gets quoted because it is the official measure of industrial activity.

PMI is faster but it is also opinion-based. A few cautious purchasing managers can swing the index even if actual output stays the same.

When to use which

Use PMI when

• You want an early read before the RBI policy meeting
• You are timing a sector rotation in your portfolio
• You are tracking month-to-month momentum, not absolute level
• You need cross-country comparisons (PMI uses the same methodology globally)

Use IIP when

• You need the exact growth rate for the past quarter
• You are looking at a specific industry segment (capital goods, consumer durables)
• You want data the government uses for GDP estimates
• You need long historical series for back-testing

The catch with each indicator

IIP catches

The base year was set in 2011-12 and has not been revised. That makes the weights outdated, especially for sectors that have grown fast since (electronics, mobile phones, EVs). The newer the sector, the more IIP under-represents it.

PMI catches

It is a diffusion index, not a level. A reading of 55 only tells you more firms are growing than shrinking; it does not say by how much. A high PMI in a deep recession just means firms expect things to be slightly less bad next month.

How to read them together

1. Track PMI on the first day of every month for the early signal.
2. Cross-check with the IIP release in the second half of the same month.
3. If they agree, the signal is strong.
4. If they disagree, trust PMI for direction and IIP for magnitude.
5. Pair both with capacity utilisation from the RBI OBICUS survey for the full picture.

The official IIP release calendar is on the RBI website Real Sector Statistics section, and the PMI release calendar sits with S&P Global's India page.

Common misreads to avoid

Many readers treat a single monthly print as a verdict. One number is noise. Take a three-month rolling average for IIP and a two-month average for PMI before drawing any conclusion about a turn in the manufacturing cycle.

Another common mistake is comparing the absolute IIP number to the PMI level. They are different scales. Compare the direction of change instead, and only after both have moved for at least two months in the same direction.

The verdict in one line

For real-time manufacturing health, PMI wins. For the official record of how much was produced, IIP wins. A serious investor watches both and weights them by the question they are trying to answer.

Frequently Asked Questions

Which is more reliable, IIP or PMI?

IIP is more authoritative because it uses hard production data. PMI is more timely because it uses real-time surveys. Both are reliable for different purposes.

What does a PMI of 55 mean?A PMI above 50 means expansion. 55 indicates moderate growth in manufacturing activity compared to the previous month.

How often is IIP revised?

The Ministry of Statistics revises IIP twice: a first revision after one month and a final revision after two months. Both are minor in most cases.

Can PMI predict GDP growth?

PMI is one of the best leading indicators of GDP growth, especially for the manufacturing component. Sustained PMI above 55 typically aligns with strong quarterly GDP prints.