EXHIBIT 10.24

AMENDMENT NO. 1 TO

EXPONENT, INC.

1998 NONSTATUTORY STOCK OPTION PLAN

RECITALS:

A. The Board of Directors of Exponent, Inc., a Delaware corporation (the
“Company”), previously adopted the 1998 Nonstatutory Stock Option Plan (the
“1998 Plan”).

B. In light of revised proxy statement disclosure requirements of the Securities
and Exchange Commission, on January 29, 2007 the Board of Directors approved the
following amendment to the definition of “Fair Market Value” in the 1998 Plan.

AMENDMENT:

1. DEFINITION OF “FAIR MARKET VALUE”

Effective as of January 29, 2007, Section 2(m) of the 1998 Plan is hereby
amended and restated as follows:

“(m) “Fair Market Value” means, as of any date, the value of Common Stock
determined as follows:

(i) If the Common Stock is listed on any established stock exchange or a
national market system, including without limitation the Nasdaq Global Market or
The Nasdaq Global Select Market, its Fair Market Value shall be the closing
sales price for the Common Stock as quoted on such exchange or system on the
date of determination, or if the Shares are not trading on such date, then the
closing price for the Common Stock on the last preceding trading day on which
sales of the Shares are reported as having occurred, as reported in The Wall
Street Journal or such other source as the Administrator deems reliable;

(ii) If the Common Stock is regularly quoted by a recognized securities dealer
but selling prices are not reported, the Fair Market Value of a Share of Common
Stock shall be the mean between the high bid and low asked prices for the Common
Stock on the date of determination, or if no prices are quoted for such date,
then the mean between the high bid and low asked prices on the last preceding
trading day on which any bid and asked prices were quoted, as reported in The
Wall Street Journal or such other source as the Administrator deems reliable; or

(iii) In the absence of an established market for the Common Stock, the Fair
Market Value shall be determined in good faith by the Administrator.”

2. MISCELLANEOUS

Except as expressly modified by this Amendment, the terms of the 1998 Plan
remain in full force and effect.