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Espionage by the Numbers:
A Statistical Data Base

By Lynn F. Fischer
DSS/Security Research Center

The Security Research Center maintains an unclassified espionage case database in order to gain a better understanding of the crime of espionage. Much is known about individual espionage cases from detailed investigative reports after the arrest. But it is difficult to make sound generalizations about this type of behavior without data on a wide range of variables for many cases.

The SRC database includes information on all Americans arrested and convicted of espionage against the U.S. since World War II. It contains information on over 100 variables for 148 cases from 1945 to through 1998. It is based only on media reports, trial records, and other unclassified documents so information on quite a few cases is incomplete. 1

This database makes it possible to analyze basic information on the personal background and characteristics of the offenders, methods and motivations, and pertinent facts about the crime itself – situational features, what was lost or compromised, and consequences for the subjects. For example, we might want to know what sort of people have been arrested, why they did it, how they got involved, what if anything they were paid, and what foreign interest received (or was intended to receive) the information.

The following table shows that 87 offenders (62%) were volunteer spies -- they initiated the activity themselves, usually by contacting foreign representatives. An additional 24 spies were recruited by family or friends, most of whom had also volunteered (as in the Walker and Conrad spy rings). Only 29 -- less than a fourth -- were recruited on the initiative of a foreign intelligence service. Although not shown in the table, it is noteworthy that the percentage of offenders who were volunteers rather than recruited spies has been higher since the 1980s than during the previous decades.

Age Espionage Began by Volunteer and Recruited Spies

Volunteers Recruited by
Family or Friends
Recruited by
Foreign Intelligence
% Number
of Cases
% Number
of Cases
% Number
of Cases
<20 8 7 4.2 1 0 0
20-24 28.7 25 37.5 9 6.9 2
25-29 12.7 11 20.8 5 34.5 10
30-34 14.9 13 12.5 3 6.9 2
35-39 12.7 11 12.5 3 13.8 4
40-44 12.7 11 4.2 1 24.1 7
45+ 10.3 9 8.3 2 13.8 4
Total 100% 87 100% 24 100% 29

This table also shows the relationship between the age at which the subjects first became involved with espionage as well as whether the offenders were volunteers or recruited. The largest group of volunteers and of those recruited by friends or family were between age 20 and 24. The largest number of those who were recruited by foreign intelligence were between 25 and 29 years old. Those recruited on the initiative of a foreign intelligence service tended to be older (median age 35) than both volunteers (30) and those recruited by family or friends (25.5).

The most significant conclusions from this table are that most Americans spies are volunteers, not recruits, and that the most vulnerable age group is employees in their 20s. The volunteer spies are overwhelmingly in the young adult category.

The following table shows that half of the American spies have been military personnel, half civilian. It also the age at which spies began their espionage. Among espionage offenders who were in the military, about two-thirds began their involvement before the age of 30, while among civilians, initial offenders tended to be older. This difference probably results from the simple fact that the military population has a lower average age.

Age Espionage Began by Military and Civilian Employment

  Military Civilian
Age % Number of Cases % Number of Cases
<20 9.9 7 1.4 1
20-24 37.5 27 15.3 11
25-29 19.4 14 18.1 13
30-34 12.5 9 12.5 9
35-39 13.9 10 11.1 8
40-44 6.9 5 20.8 15
45+ 0.0 0 20.8 15
Total 100% 72 100% 56

The following table offers a positive note -- that 26% of all offenders were caught before they could do any damage, and 47% were caught during their first year of betrayal. Many of the young military offenders have been stopped in their tracks. Military offenders are more likely than civilian offenders to be apprehended in the early stages of their crime.

Length of Espionage by Military and Civilian

  Military Civilian
Length of Espionage % Number of Cases % Number of Cases
Intercepted First Time
Attempted Espionage
37.0 27 16.9 12
Less than 1 year 19.2 14 21.3 16
1 – 4.9 years 24.7 18 37.3 28
5 years or more 19.2 14 25.3 19
Total 100% 73 100% 75

The following table compares three categories of offenders with respect to their reported motivations. Motivation as coded in the database is based only on publicly available information. Actual motivation is difficult to assess, as it is often different from what appears on the surface. Many offenders had mixed motivations, in which case all significant motivations are recorded in the data base.

Motivation of Volunteer and Recruited Spies

Reported Motivation Volunteers Recruited by
Recruited by
Foreign Intelligence
  % N % N % N
Money 72.7 64 56.0 14 53.5 16
Ideology 19.3 17 36.0 9 30.0 9
Disgruntlement/Revenge 36.4 32 4.0 1 16.7 5
Ingratiation 17.0 15 60.0 15 3.3 1
Coercion 0.0 0 4.0 1 20.0 6
Thrills/Self-Importance 12.5 11 0.0 1 10.0 3
Disillusionment 11.4 10        
Recognition 3.4 3        
* One offender may have several different motivations

According to this evidence, financial gain played the major role among volunteers but was important for many recruits as well. Disgruntlement and revenge were far more prevalent among volunteers than recruits. Not surprisingly, those recruited by family or friends were more often motivated by ingratiation (the desire to please or satisfy) than by anything else. Recruitment by coercion was rare. Although not shown in the table, the full data base shows that ideology as a motivation diminished sharply after the 1940s.

Although money appears to top the list of motivations attributed to these offenders, it is interesting to see how few received any significant amount of payment before being arrested. Almost half received nothing because of early detection or because they acted from non-mercenary motives. Only ten received $100,000 or more — usually paid over long periods of time. In most cases, the financial pay-off to the espionage offender is nil or next to nothing when compared to the high risk of getting caught or the monumental cost to the nation from compromised weapon systems, lost technology lead-time, or neutralized intelligence collection systems.

Estimate of Money Received

Amount Number of Cases
None 51
$50-1,000 14
$1,000-10,000 16
$10,000-100,000 22
$100,000-1,000,000 8
$1,000,000 or more 4
Total Cases 115

Security officers have assumed for years that foreign personal contacts, especially family ties and other ties of emotion or obligation, add an element of vulnerability to recruitment for espionage. This is why foreign connections are an area of focus in background investigations. The numbers lend credence to this assumption.

Thirty-nine percent of Americans arrested for espionage had foreign relatives.  This is substantially higher than the percentage of cleared personnel in general who have foreign relatives. The actual percentage may be higher than 39%, as the available unclassified information was insufficient in many cases to determine whether or not an offender had foreign relatives.

Although not shown in the table, it is noteworthy that the foreign relative played no role in the recruitment in most cases. Also, in a majority of the cases, the foreign relative was located in or was from a friendly country rather than a hostile country.

Foreign Relatives by Volunteer and Recruited Spies

  Volunteered Recruited by
Family or Friends
Recruited by
Foreign Intelligence
  % Number of Cases % Number of Cases % Number of Cases
33.0 29 32.0 8 70.0 21
No Foreign
33.0 29 16.0 4 20.0 6
Unknown 34.0 30 52.0 13 10.0 3
Total 100% 88 100% 25 100% 30

Here are a few additional highlights from this database that give us additional understanding about motivations and situational factors leading to espionage:

  • Over 42% of the offenders are known to have been involved in drug or alcohol abuse. The actual figure may be higher, as there are many cases in which the unclassified record is insufficient to make a judgment on this subject. Those who were caught before classified information was even passed were more likely to be substance abusers than those who succeeded in committing espionage.
  • Of the 148 offenders, 6 were homosexual, 106 heterosexual, and the sexual orientation of the remaining 36 is not known from the unclassified record. Homosexuality is not known to have been a significant factor in any of the cases.
  • Volunteer spies were more likely to fail in their effort to pass information to foreign interests. Almost 40% of the volunteers were caught in the act, whereas only 7% of the recruited spies were intercepted before they could damage national security.

1. Information about this database and data on additional variables are available in the report by Suzanne Wood and Martin F. Wiskoff, "Americans Who Spied Against Their Country Since World War II." Monterey, CA: Defense Personnel Security Research Center, May 1992. That report is being updated.