View original document

The full text on this page is automatically extracted from the file linked above and may contain errors and inconsistencies.

Authorized for public release by the FOMC Secretariat on 09/04/2018

BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM
DIVISION OF MONETARY AFFAIRS

Date:

June 5, 2001

To:

Don Kohn

From:

Bill English and Antulio Bomfim

Subject:

Measures of the Equilibrium Real Federal Funds Rate Employed in the May
Bluebook

This memorandum provides a brief description of the different measures of the
equilibrium real federal funds rate that were used in the creation of the chart shown in
the May bluebook.' The chart (a revised copy of which is attached) showed the range
between the highest and lowest of five such measures. 2 Recent values of each of the
five series are shown in Table 1.
The equilibrium real rate concept employed in the construction of these
measures is based on the medium-term dynamics of the economy, a time frame that
seems most relevant for the conduct of monetary policy. As a result, these equilibrium
real rate measures are not intended to capture the full long-run equilibrium of the
economy.³ The measures also abstract from the short-term effects of purely
"transitory" economic shocks, meaning shocks having dynamics that dissipate within a
few years. Such transitory shocks may well lead the FOMC to set the intended federal
funds rate at a level other than its equilibrium level for some time.

1. The real federal funds rate is defined here to be the nominal federal funds rate less the
percentage change in core PCE prices over the previous four quarters.
2. The "current rate" shown in the chart is the rate after the May FOMC meeting. Some

minor corrections have been made to the various real funds rate series, but the effect on the
chart of these adjustments is quite small.
3. Simulations of the FRB/US model suggest that long-run equilibrium real rates typically
correspond to a horizon of several decades.

Authorized for public release by the FOMC Secretariat on 09/04/2018
Chart 3
Actual Real Federal Funds Rate and
Range of Estimated Equilibrium Real Rates
Percent
5
Quarterly
Actual Real Funds Rate

4

Historical Average: 2.81
.....

(1966Q1-2001Q1)
~. ....................................
~ ~
~-----

Current Rate

0

-

111111111111111111111111111111111111111111111
1990

1992

1993

1994

1995

1996

1997

1998

1999

2000

III
2001

Note: The shaded range represents the maximum and the minimum values each quarter of the five estimates of the equilibrium real federal funds
rate described in the text. Real federal funds rates are calculated using four-quarter lagged core PCE inflation. The values of the real federal
funds rate in the second quarter of 2001 include the staff projection of core PCE inflation for that quarter.

Authorized for public release by the FOMC Secretariat on 09/04/2018

1, both of these measures of the equilibrium real funds rate have declined substantially
of late.
The Statistical-Filter-BasedMeasures5
The statistical-filter-based measures of the equilibrium real federal funds rate
are estimated by Thomas Laubach and John Williams based on a two-equation model.
The first equation-essentially a traditional IS curve-links the output gap to past values
of the output gap, past deviations of the real federal funds rate from its (unobserved)
equilibrium value, and an error term. Thus, even if the funds rate is at its equilibrium
value, output will differ from its trend value as a result of the error term as well as the
short-run dynamics caused by past differences between output and its trend value. The
second equation indicates that the equilibrium real federal funds rate is a random
walk-i.e., changes in the equilibrium real rate are unforcastable. The parameters of this
model are estimated jointly with one-sided filter estimates of the equilibrium real
interest rate in each period-that is, estimates based only on data from previous
periods-using a Kalman filter. These one-sided estimates are then improved upon by
using the full data sample in a two-sided statistical filter (the "Kalman smoother").
As in the case of the quarterly model, two series of equilibrium real rates were
calculated using this method. The first series is based on data only through
2001Q3-using the staff projections of the output gap and the real federal funds rate for
2001Q2 and 2001Q3-to derive estimates of the equilibrium real rate through 2001Q2.
(The use of the third quarter data is necessary given the lags in the assumed relationship
between the output gap and the real federal funds rate). The second series is based on
the actual output and real federal funds rate data augmented by the staff projection
through 2002Q4. As shown in the attached table, the inclusion of the staff projection in
the dataset causes a significant reduction in the estimate of the current equilibrium real
federal funds rate.

5. This method is described in Thomas Laubach and John Williams "Estimates of a Timevarying Equilibrium Real Federal Funds Rate," memorandum to the Board of Governors,
December 14, 2000.

Authorized for public release by the FOMC Secretariat on 09/04/2018

The Indexed-Treasury-BasedMeasure6
This measure of the equilibrium real rate, developed by Antulio Bomfim, starts
from the observation that-if term, liquidity, and convexity premiums are roughly
offsetting-the forward real interest rate implied by ten- and thirty-year Treasury
inflation-indexed securities should correspond to market participants' expectations of
average real short-term Treasury yields ten to thirty years from now. Under the
assumption that any transitory shocks will have run their course over the coming ten
years, this forward rate should provide an estimate of the medium-term equilibrium
value of real short-term Treasury yields.
In order to obtain an estimate of the equilibrium real federal funds rate, one
must adjust the equilibrium Treasury yield for the effects of taxes and risk premiums.
To do so, the forward rate is boosted to offset an assumed marginal state and local tax
rate of 11 percent as well as the average risk premium between (tax-adjusted) Treasury
bill yields and the federal funds rate over the 1962 to 2000 period. As can be seen in
the table, the resulting estimate of the equilibrium real federal funds rate is the highest
of the five in recent quarters.

6. This method is described in Antulio Bomfim, "What Do Simple Averages and Yields on
Treasury Inflation-Indexed Securities Tell Us About Equilibrium Real Interest Rates,"
memorandum to Governor Gramlich, May 11, 2001. Note that the real federal funds rates
reported in that memorandum are on an annualized basis. Additional information is provided
in Antulio Bomfim, "Deriving Equilibrium Real Interest Rate Measures from Yields on
Treasury Inflation-Indexed Securities," memorandum to Mr. Kohn, June 5, 2001.

Authorized for public release by the FOMC Secretariat on 09/04/2018
-5-

Table 1
Estimates of the Equilibrium Real Federal Funds Rate
Method

1998

1999

2000

2001Q1

2001Q2

3.8

4.1

4.2

3.7

3.5

4.5

4.6

4.4

3.8

3.7

3.8

3.7

3.5

3.3

3.3

3.6

3.5

3.1

2.8

2.7

3.9

4.2

4.2

3.9

4.0

FRB/US (employing a onesided moving average, using
projected data through
2001Q2)
FRB/US (employing a
centered moving average,
using projected data through
2002Q4)

Statistical Filter (using
projected data through
2001Q3)
Statistical Filter (using
projected data through
2002Q4)____

Indexed Treasury Securities

Note: The estimates of the real equilibrium federal funds rate were calculated using the
annualized return on federal funds less the lagged four-quarter core PCE inflation rate
calculated as a log-difference of the price index. However, for ease of comparison with
the more familiar federal funds rates on a quoted basis (which are not annualized) and
the inflation rates reported in the staff projection, the values in this table and in the
bluebook chart have been converted to a quoted basis with inflation calculated as a
simple percentage change.