Three-Lens Inflation Check
Track inflation trends, long-term levels, and real wage purchasing power
- Difficulty
- Easy
- Time to result
- ~days to results
- Steps
- 5
- Confidence
- 96%
The Three-Lens Inflation Check replaces reactions to a single headline number with a structured assessment. The first lens examines trajectory by smoothing noisy monthly data with a moving average and asking whether momentum is improving, stalling, or reversing. The second lens examines the level of inflation through year-over-year CPI, providing a more stable view of the longer-term rate. The third lens evaluates personal impact by comparing wage growth with inflation; nominal prices may be higher, but purchasing power can be maintained or improved when earnings rise as fast or faster. Together, these lenses move the user from a volatile data point to a trend, then to economic context, and finally to the practical effect on household finances.
Origin
Extracted from Masters in Business, where Barry Ritholtz summarized an investor and consumer checklist after discussing inflation with former Federal Reserve economist Claudia Sahm.
Core principles
- 01Judge the trajectory rather than one noisy release
- 02Use moving averages to reduce recency bias
- 03Measure inflation year over year for longer-term context
- 04Compare wage growth with inflation to assess purchasing power
- 05Separate the inflation rate from the lived financial impact
How to run it
- 1
Reject the Single-Print Reaction
Treat each monthly inflation release as one noisy observation rather than a definitive change in regime. Pause before changing a portfolio or financial plan because of an unusually good or bad number.
Pro tip Record the number alongside several prior releases so the surrounding pattern remains visible.
Watch out Recency bias can make the latest observation feel more informative than it is.
- 2
Smooth the Trajectory
Use a moving average to determine whether inflation momentum is generally rising, falling, or stalling. Focus on the direction sustained across multiple releases.
Pro tip Use the same averaging window consistently so comparisons remain meaningful.
Watch out A moving average reduces noise but also reacts more slowly to genuine turning points.
- 3
Check the Year-over-Year Level
Review CPI on a year-over-year basis to understand where inflation stands over a longer horizon. Compare the current level with the central bank's target and its recent trend.
Pro tip Look beneath the headline when volatile food or energy components dominate the move.
Watch out Year-over-year comparisons can be distorted by unusually high or low base periods.
- 4
Measure Real Wage Change
Compare the percentage change in wages or salary with the inflation rate. Determine whether earnings have preserved, increased, or lost purchasing power.
Pro tip Use your own compensation change when evaluating household impact rather than relying only on national averages.
Watch out A higher nominal salary does not improve purchasing power when it trails inflation.
- 5
Make the Contextual Decision
Combine trend, level, and purchasing-power findings before acting. Adjust financial decisions only when the lenses collectively indicate a meaningful change rather than temporary turbulence.
Pro tip Write a one-sentence conclusion for each lens before making a decision.
Watch out Do not treat this framework as a precise forecast of the next Federal Reserve action.
In the wild
An investor sees one hotter-than-expected CPI release and considers selling bonds immediately. The three-month moving average still shows declining momentum, year-over-year CPI remains below its level six months earlier, and the investor's salary growth exceeds inflation. The investor recognizes the report as turbulence within an improving trend and keeps the existing allocation pending more evidence.
→ The investor avoids a recency-driven portfolio change based on one noisy release.
A household notices that groceries and services cost more than they did a year earlier. They compare their annual salary increase with year-over-year CPI and find that earnings rose by less than inflation. Although inflation momentum is falling, their purchasing power has still declined, so they revise discretionary spending while preserving long-term investments.
→ The household distinguishes falling inflation from falling prices and responds to its actual real-income position.
Common mistakes
Trading the Latest Number
Reacting to one monthly release confuses noise with a durable change in trajectory. Confirm the movement across several observations first.
Confusing Disinflation With Deflation
A falling inflation rate means prices are increasing more slowly, not necessarily declining. Evaluate the price level and purchasing power separately.
Ignoring Wage Growth
Looking only at prices misses whether income has risen enough to offset them. Compare percentage wage growth directly with inflation.
Is it for you?
Best for
It is best for investors and households interpreting inflation data before making portfolio, borrowing, or spending decisions.
Not ideal for
It is not sufficient for short-term inflation trading or forecasting Federal Reserve decisions without broader labor-market and component-level data.
From the transcript
“Don't let any single month's data point throw you off. Use a moving average.”
“You have to look at the trend.”
“Hopefully your salaries have risen enough or more than inflation to maintain your buying power.”
From the episode
At the Money: Knowing When You've Whipped Inflation