Level-and-Channel Macro Test
Test economic narratives against logged data levels and historical trend channels
- Difficulty
- Moderate
- Time to result
- ~weeks to results
- Steps
- 6
- Confidence
- 95%
This method begins with a major component of the economy, such as real personal consumption expenditures, and plots its level instead of a volatile period-to-period growth rate. The level is transformed into logarithms so a stable percentage growth rate appears as a comparable linear trend. A channel is then drawn around the pre-shock path, and current observations are evaluated by their position within, above, or below that channel. A collapse followed by a return to the same channel suggests normalization rather than a permanently altered trajectory. Because consumption represents most US GDP, continued movement near its historical channel provides a powerful check against recession forecasts. The method does not prove that a downturn is impossible; it forces the analyst to reconcile a bearish narrative with the behavior of the economy's largest components.
Origin
Extracted from Masters in Business, where Binky Chadha explained how he tested recession forecasts using real personal consumption spending.
Core principles
- 01Data levels can reveal stability hidden by volatile growth rates.
- 02Logarithms make long-run proportional growth easier to compare.
- 03Trend channels provide context for temporary shocks and recoveries.
- 04Large economic components deserve priority over dramatic minor indicators.
- 05Narratives should be challenged when dominant data series remain on trend.
How to run it
- 1
Choose the Dominant Series
Identify the economic component that contributes most directly to the outcome being forecast. For US GDP, Chadha begins with real personal consumption spending because it represents roughly seventy percent of activity.
Pro tip Start with components that have both large economic weight and a long, consistent history.
Watch out A dramatic but economically small indicator can distract from the broader trajectory.
- 2
Plot the Real Level
Use the inflation-adjusted level of the series instead of relying only on annualized or quarter-over-quarter growth rates. This makes the cumulative trajectory and recovery from shocks visible.
Pro tip Keep the untransformed chart available as a reasonableness check.
Watch out Growth rates can exaggerate base effects after a collapse or rebound.
- 3
Apply a Log Transformation
Take logarithms of the level so constant percentage growth can be represented by a stable linear slope. This enables comparisons across periods with very different absolute values.
Pro tip Label the transformation clearly so readers do not mistake logged values for raw units.
Watch out Do not use logarithms for series containing zero or negative values.
- 4
Draw the Historical Channel
Estimate the pre-shock trend and place reasonable upper and lower bounds around it. The channel defines the range of historically normal variation.
Pro tip Use a sufficiently long but economically relevant pre-shock period.
Watch out An overly wide channel can make the test meaningless, while an overly narrow one creates false alarms.
- 5
Locate the Current Path
Determine whether the latest level is inside, above, or below the channel and whether it is moving back toward or away from trend. Distinguish a temporary interruption from sustained divergence.
Pro tip Examine revisions before declaring that the series has permanently left its channel.
Watch out A return to trend in one component does not eliminate risks elsewhere.
- 6
Reconcile the Narrative
Compare the channel evidence with the prevailing economic forecast. Demand a clear explanation whenever the consensus predicts recession while a dominant component continues along its historical path.
Pro tip Repeat the test across several major components before making a portfolio decision.
Watch out Trend persistence is evidence, not a guarantee that the next shock will resemble the last one.
In the wild
Real personal consumption spending followed a tight channel before the pandemic, collapsed during the shock, and then recovered to approximately the same channel. It continued around that path while recession forecasts persisted and the Federal Reserve tightened policy aggressively.
→ The chart provided evidence against repeated near-term recession calls and supported a constructive view of US growth.
Applying a similar trend comparison showed the United States returning to its previous growth path while European activity stalled after Russia's invasion of Ukraine. The gap relative to Europe's trend highlighted potential recovery room if growth resumed.
→ The relative channel analysis supported an early overweight position in European equities alongside the United States.
Common mistakes
Plotting Only Growth Rates
Short-period growth rates are noisy and dominated by base effects. They can hide the fact that the underlying level remains on a stable path.
Ignoring Economic Weight
A recession thesis should not be built from minor indicators while the largest components of GDP remain near trend without an explicit reconciliation.
Treating Every Return to Trend as Permanent
A series can re-enter its channel and later leave it again. Continue monitoring the direction and corroborate it with other components.
Is it for you?
Best for
It is best for investors evaluating macroeconomic consensus forecasts and claims of structural economic change.
Not ideal for
It is not ideal when the selected series has undergone a genuine definitional or structural break that invalidates its historical channel.
From the transcript
“So I just plot the level.”
“You have to take logs because of we all though why we should take logs, And then I draw channels around it.”
“Pandemic collapse, recovery of pce back magically into exactly the same channel magic”
From the episode
Getting Earnings Right with Deutsche Bank's Binky Chadha
Binky Chadha