An experimental investigation of personality types impact on pair effectiveness in pair programming

Abstract

In this paper, pair programming is empirically investigated from the perspective of developer personalities and temperaments and how they affect pair effectiveness. A controlled experiment was conducted to investigate the impact of developer personalities and temperaments on communication, pair performance and pair viability-collaboration. The experiment involved 70 undergraduate students and the objective was to compare pairs of heterogeneous developer personalities and temperaments with pairs of homogeneous personalities and temperaments, in terms of pair effectiveness. Pair effectiveness is expressed in terms of pair performance, measured by communication, velocity, design correctness and passed acceptance tests, and pair collaboration-viability measured by developers’ satisfaction, knowledge acquisition and participation. The results have shown that there is important difference between the two groups, indicating better communication, pair performance and pair collaboration-viability for the pairs with heterogeneous personalities and temperaments. In order to provide an objective assessment of the differences between the two groups of pairs, a number of statistical tests and stepwise Discriminant Analysis were used.

Appendices

Appendix 1

Communication Transactions Form

Α/Α	Dev. code No.	Requirements (add/delete /modify)	Specification/Design (add/delete /modify)	Coding (add/delete /modify)	Unit testing (add /delete/modify)	Review code/design	Other (describe)
1
2
3
4
5
6
7
8
9
10
11
12	:	:		:	:		:

Write developer code number and tick the appropriate communication mode

Appendix 2

Questionnaire (for pair collaboration-viability)

Appendix 3

The following descriptions refer to the Keirsey type, each type contribution to the population, and descriptive list of identifying characteristics. These descriptions have been extracted from Keirsey and Bates (1984).

3.1 Personalities

Extroverting (E)–Introverting (I)

Extroverts get their energy from the outside world, from experiences and interactions, while Introverts from within themselves, from their internal thoughts, feelings, and reflections. Extroverts tend to talk easily about anything, whereas Introverts are comfortable with long silences. Introverts prefer finished ideas, namely to read and think about something before start talking, so we must give them time to process new information, especially in meetings. For interactions with users and management, Extroverts are better in talking (and getting responses), and at presenting ideas than Introverts.

Sensing (S)–Intuiting (N)

Sensors gather information linearly and tend to take things literally and sequentially, preferring tangible results clearly described. They are observant of what is happening around them, and are especially good at recognizing the practical realities of a situation. Their concentration to details makes them the most capable programmers. Intuitives like to gather information more abstractly (seeing the big picture), focusing on the relationships and connections between facts. They prefer to speak in concepts and global futuristic ideas and they are good at seeing new possibilities and different ways of doing things. Therefore, they can be used more as system analysts determining users/clients' needs and identifying problems in systems.

Thinking (T)–Feeling (F)

Thinkers make decisions based on objective information, while feelers are based on subjective information. Thinkers, tend to be logical, critical, orderly, and prefer to work with facts. They examine carefully cause and effect of a choice or action to enhance their problem-solving abilities. Their tendency to be logical is needed mostly in programming. Feelers, driven by personal values, make decisions considering what is important to themselves and others. Their strengths include understanding, appreciation and support of others. They tend to be more people-oriented and good team-builders.

Judging (J)–Perceiving (P)

The most problems concerning communication are caused by differences in the work styles. Judgers tend to live in an orderly and planned way, with detailed schedules. They like things decided and concluded and they prefer a bad decision than no decision. Perceivers tend to live in a flexible, spontaneous way, are based on experience and have open issues. They like to explore every possibility, and consequently have difficulty making decisions working on deadlines. On the contrary Judgers prefer to avoid last-minute stresses, and try to conclude quickly: once they have found a good solution they accept it and move on to something else. A combination of Judgers and Perceivers in a pair would help to ensure that the best solution will be found in a reasonable time.

3.2 Temperaments

Artisans and guardians prefer concrete communications, while idealist and rational prefer more abstract communications. Artisan and rational types prefer a cooperative path to goal accomplishment, while guardian and idealist types prefer more a utilitarian approach. Artisans, combining a sensor’s sense of reality and a perceiver’s spontaneity, feel most comfortable with clear and direct communications in cooperative pursuit of a goal. Possessing a correct sense of timing, they are great start-up persons, are lateral thinkers, problem solvers and great brainstormers. They are troubleshooters proposing practical solutions and making quick decisions. Their adaptability and sense of innovation can help the pair achieve requirements with new technology.

Guardians, combining a sensor’s sense of reality and a judger’s desire for reaching a conclusion, are traditionalists and stabilizers. They are good as administrators, establishing policies, rules, schedules, regulations and a functioning hierarchy. However, they do not easily perceive project delays or problems. Because of a strong need for conclusions, they may not allow enough time for processing. They tend to want things to remain the same, without allowing for sparks of creativity or innovation. They will not be very successful in times of rapid change.

Combining an intuitive’s focus on the relationships and a feeler’s preference in personal values, Idealists are successful in leveraging their own and other people skills. They like to guide others and are committed to the progress of the people in a given setting. They are also transactional as Artisans, excellent communicators and people motivators. An Idealist developer adds a personalised touch to a pair, contributing to team spirit and morale. However, he does not react well to sudden changes.

Rationalists, combining the objectivity of the thinkers and the visionary of the intuitives, are described as theorists, innovators, systems planners and architects of change. They focus on competence and excellence, valuing high logic and reason, adopting a logical and strategic analysis approach of resolving issues. Thus their most practiced and successful operations tend to be planning, inventing and configuring.

Appendix 4

Samples of checklists and the associated grading schemes.

4.1 Coffee Machine

The coffee machine serves coffee for 35 cents, with or without sugar and creamer. The coffee list includes: black (without sugar and cream powder), white (with cream powder), sweet (with sugar), sweet_white (with sugar and cream powder). The front panel will have four buttons (choice menu with the four types of coffee). There will also be a coin return button. The machine will take euro coins only (max 1 Euro), and give changes. This design consists of 12 classes:

Classes	Responsibility-driven design (RD)
CoffeeMachine	Initiates the machine; knows how the machine is put together; handles input
CashBox	(to be implemented)
FrontPanel	Knows selection; coordinates payment; delegates drink making to the product.
Product	Knows its recipe and price.
ProductRegister	Knows what products are available.
Recipe	Knows the ingredients of a given product; tells dispensers to dispense ingredients in sequence.
Dispensers	Knows which ingredient it contains; controls dispensing; tracks amount it has left.
DispenserRegister	Knows what dispensers are available
Ingredient	Knows its name only.
Output	Knows how to display text to the user.
Input	Knows how to receive command-line input from the user
Main	Initializes the program

4.2 First Assignment—Cash Administration

Please make the following changes:	Sub Tasks	Points
Start the machine, inputting a cash amount (i.e. 10,000 cents).	Design	0.5
	Code-unit-tests	1.0
Make customer transactions:	Design	0.5
Give change, checking the amount.	Code-Unit-tests	0.5
Display the proper message if the amount is not enough, and	->>-	0.5
Input new amount.	->>-	0.5
End of function:	Design	0.5
Print the total amount of transactions and	Code-unit-tests	0.5
The cash balance.	->>-	0.5

4.3 Second Assignment—Transactions’ Statistics

Please make the following changes:	Sub Tasks	Points
Make customer transactions:	Design	0.5
Log each sale transaction.	Code-unit-tests	0.5
End of function:	Design	0.5
1. Sort transactions in descending order.	Code-Unit-tests	2.0
End of function:	Design	0.5
2. Print in a descending order the most sold coffee types.	Code-unit-tests	1.5

The final grade is calculated by summing the points of each sub task.

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