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May 31, 2006

Valley Wag

ValleyWag trots around Silicon Valley: example.

May 30, 2006

Best-Practices in Mortgage Default Risk Measurement and Economic Capital

Best-Practices in Mortgage Default Risk Measurement and Economic Capital

Each of the major processes used by industry participants to measure
so-called “credit risk” for first mortgage products. The study has three

Section I provides a discussion of the general concept of Economic
Capital (“EC”), how EC is measured and used by best-practice banks,
and how EC concepts used by industry practitioners differ from
regulatory definitions of capital.

Section II discusses the various types of theoretical “credit risk
models” that are used by practitioners to measure EC for mortgages.

Section III conducts several empirical experiments in which large
historical databases are used to estimate the credit risk models
described in Section II. The empirical work is aimed at helping
the practitioner and the regulator to evaluate the results of
alternative models.

David Kaskowitz, LoanPerformance
Kyle Lundstedt, LoanPerformance
Alexander Kipkalov, Washington Mutual Inc.
John Mingo, Mingo & Co.

May 29, 2006

Time Dependent Data Exploration And Preprocessing

Time Dependent Data Exploration And Preprocessing:
Doing It All by SAS.

Exploration and preprocessing methodology of transactional data,
transform the data into a multivariate time series and select an
adequate model for analysis.

Unlike time series data, where observations are equally spaced by
a specific time interval, in transactional data, observations are not
spaced with respect to any particular time period. Our approach is
illustrated using observations of length of stay (LOS) of a patient
at a hospital Emergency Department (ED). The challenges of analyzing
these data include autocorrelations of the observations, non-linearity,
and the fact that observations were not recoded at regular time

First, using the SAS procedure, PROC HPF, we transformed the
transactional data set into multivariate time series data. Next, a
series of specialized plots such as histograms, kernel density plots,
boxplots, time series plots, and correlograms were produced using
the SAS procedure PROC GPLOT to capture the essentials of the
data to discover relationships in the variables, and to select an
optimal model of analysis. As a result of this step by step
preprocessing methodology, adequate models of analysis of
LOS were identified and the dimension of the data set was
reduced from 3345 observations to only 256 observations.

Joseph Twagilimana, University of Louisville, Louisville, KY [PDF]

See also Hospital Length of Stay: Mean or Median Regression.

May 28, 2006

Mortgage handbook at Treasury

Mortgage Banking, Comptroller’s Handbook (March 1998)

Sample entry:
Price level adjusted mortgage (PLAM). A mortgage loan in
which the interest rate remains fixed, but the outstanding
balance is adjusted for inflation.


May 26, 2006

House Price CAPM

Cointegration and Error Correction Mechanism Approaches:
Estimating a Capital Asset Pricing Model (CAPM) for House
Price Index Returns with SAS

Many researchers erroneously use the framework of linear
regression models to analyze time series data when predicting
changes over time or when extrapolating from present conditions
to future conditions. Caution is needed when interpreting the results
of these regression models. Granger and Newbold (1974) discovered
the existence of ‘spurious regressions’ that can occur when the
variables in a regression are nonstationary. While these regressions
appear to look good in terms of having a high R2 and significant
t-statistics, the results are meaningless. Both analysis and modeling
of time series data require knowledge about the mathematical model
of the process.

This paper introduces a methodology that utilizes the power
of the SAS DATA STEP, and PROC X12
and REG procedures. The DATA STEP uses the SAS LAG and
DIF functions to manipulate the data and create an additional
set of variables including Home Price Index Returns (HPI_R1), first
differenced, and lagged first differenced. PROC X12 seasonally
adjusts the time series. Resulting variables are manipulated
further (1) to create additional variables that are tested for
stationarity, (2) to develop a cointegration model, and (3) to
develop an error correction mechanism modeled to determine
the short-run deviations from long-run equilibrium. The relevancy
of each variable created in the data step to time series analysis is
discussed. Of particular interest is the coefficient of the error
correction term that can be modeled in an error correction mechanism
to determine the speed at which the series returns to equilibrium. The
main finding is that Metropolitan Statistical Areas (MSAs) with very
slow shortrun acceleration paths to the equilibrium have higher
returns and risk associated with house price returns than
MSAs with very rapid speed-of-adjustment coefficients.

-- Ismail Mohamed and Theresa R. DiVenti, PDF.

May 25, 2006

Unobserved Components Model, Proc UCM

Underlying model and several of the features of Proc UCM, new in the
Econometrics and Time Series (ETS) module of SAS .

Time series data is generated by marketers as they monitor “sales by month”
and by medical researchers who collect vital sign information over time. This
technique is well suited to modeling the effect of interventions (drug administration
or a change in a marketing plan). This new procedure combines the flexibility of
Proc ARIMA with the ease of use and interpretability of Smoothing models.

UCM does not have the capability to easily model transfer functions, a useful
ARIMA function that is planned for Proc UCM.

An Animated Guide©: Proc UCM (Unobserved Components Model)
Russ Lavery, Contractor for ASG, Inc., PDF

May 24, 2006

Econometric notes

Econometric course notes by John Aldrich.

May 23, 2006


Seemingly unrelated regressions and simulateous equations: PDF

May 22, 2006

Statespace is SAS

Statespace in SAS/ETS.

The STATESPACE procedure analyzes and forecasts multivariate
time series using the state space model. The STATESPACE procedure
is appropriate for jointly forecasting several related time series that
have dynamic interactions. By taking into account the autocorrelations
among the whole set of variables, the STATESPACE procedure may
give better forecasts than methods that model each series separately.

May 21, 2006

Snap job

Snap Job Search.
Best use of incremental search partitioning and refinement
of multi-faceted search and browsing.

Snap journal.

Battelle comments.

May 20, 2006

Treo 700p raves, rants

Treo (Handspring) 700p is out. With PalmOS.
Pague raves.
Palm Infocenter
Palm Addict

Check the service contract: An internet without uploading or downloading.

Verizon's contract, for example, says its service cannot be used for uploading,
downloading or streaming of movies, music or games; it also prohibits peer-to-
peer file sharing and Internet phone calling, known also as VoIP.)

-- NYT.

May 19, 2006

Trader Feed, Trader Psychology

Trader Feed opines on trading strategy and psychology.
By author of Psychology of Trading (Wiley, 2003) using
historical patterns in markets, Brett Steenbarger.
EX: feeling momentum.

May 18, 2006

Random Roger investing

Random Roger invests his portfolio,
and explains how, in the WSJ.

May 17, 2006

Sommelier smackdown

Sommelier smackdown, amused by guy who conflates
take-out and take-in outcall and incall.

Blackpepper nuances' that `explode on the back palate
supported by fine grained tannins and long plum and spice

May 16, 2006

The Quant / Richard Booth

THE QUANT by Richard Booth: about the intersections of law, business, finance,
economics, and statistics. A law Professor.

May 15, 2006

NumSum spreadsheets on the web

Spreadsheets put on the web by NumSum.
Like Flickr for accountants.

[via Altos Research]

May 14, 2006

Matrix @ Miller Samuel

Home buying reasons vary by generation and that open
houses are now on iPod video.
-- Matrix at Miller Samuel.

May 13, 2006

Governance: Gore 2008 ?

Governance could be worse. Draft Gore 2008.
Also: Ozone Man's Climate Crisis and SNL address
-- YouTube (Flash), C & L (QuickTime).

As for immigration, solving that came at a heavy cost, and I
personally regret the loss of California.

Previously: Al Gore's heart and soul, protecting our children
from the dangers of smoking.

May 12, 2006


STL BMW CCA aka STL BMW Club gave a great technical event: Gateway Tech.

May 11, 2006

Footnoted Edgar files

Footnoted reads SEC filings, Edgar's fine print.

May 10, 2006

Mortgage Payment Reset: only a 1% problem

Mortgage Payment Reset: The Rumor and the Reality.

Our nation is a $10 trillion-per-year economy currently possessing
$19 trillion in household asset value and $11 trillion in homeowner’s
equity. Losses of $110 billion – spread over several years – would
come to only about one percent of the total national homeowners’

Currently the economy is growing at about 3 percent per year,
adding about $300 billion per year to our national income. Losses
of $30 billion in a year would consume only one-tenth of this
increase, the equivalent of slowing the growth rate from 3% to 2.7%.
According to the Mortgage Bankers Association of America, mortgage
lending totals from $2 trillion to $3 trillion per year. The yearly reset
losses anticipated by this paper would constitute only about one
percent of the total annual lending amount.

Christopher Cagan, director for research and analytics at
First American Real Estate Solutions. PDF
[via NYT]

May 9, 2006

Graham and Dodd breed optimism

Stephen Roach of Morgan Stanley New York revisits value analysis by Graham and Dodd.
Optimistic ?

Refs: Security Analysis by Benjamin Graham and David Dodd.

May 8, 2006

For money

Dilbert's war for money.

May 7, 2006

Gratuitous trackback.

Cited, customized.

May 6, 2006

Ideoblog busmovie / Larry E. Ribstein

Corporate law and governance are topics of Ideoblog Ribstein. Examples:
Gretchen Morgenson on corporate governance, the state's role in changing corporate contracts.

May 5, 2006

Chicago personal injury lawyer or New York lasik

Chicago personal injury lawyer or New York lasik laser eye surgery are
valuable search words.

So hire a Chicago personal injury lawyer if your New York lasik fails.

Again, lawyer.

May 4, 2006

Mortgage refinancing, optimized

Mortgage Valuation and Optimal Refinancing, Pliska (2006)

Landholders, Residential Land Conversion, and
Market Signals
, Margulis (2006)

Mortgage Payment Reset: The Rumor and the Reality,
Christopher Cagan (2006)

Option-Theoretic Prepayment Model for Mortgages,
Fabozzi, Kalotay and Yang. (2004)

The Complexities of Mortgage Options,
Prendergast (2003)

Optimal Recursive Refinancing and the Valuation of
Mortgage-Backed Securities
, Longstaff (2002)

Best-Practices in Mortgage Default Risk Measurement and
Economic Capital
, Kaskowitz, Lundstedt (2002)

Mortgage Banking, Comptroller’s Handbook (1998)

Subprime mortgage rate spread at origination

Residential Mortgage Termination and Severity,
De Franco. (1994)

May 3, 2006

Eastern Finance Association

Financial Rounds recommends Eastern Finance Association's

May 2, 2006

Torture, VodkaPundit

Stylish Coloradoan VodkaPundit's serious thinking or linking.
Bonus points for recommending I’m An Adult Now by
The Pursuit of Happiness.
If you like TPOH, you'd like Jerry Jerry & Sons Of Rhythm Orchestra's
Battle Hymn of the Apartment.

May 1, 2006

Hockey playoff season.

Hockey playoff season.