Manpower utilization patterns in project management
San Diego State University
Like other common manufacturing and service enterprises, projects are combinations of people, equipment, and material, designed to produce together certain predetermined results. Projects, however, are not characterized by a continuous output at a given steady rate such as in mass production and process enterprises. Instead, a project constitutes a transient system, aimed at the attainment of a single objective, followed by project termination.
This article addresses the argument that common elements across diverse project life cycle patterns can be delineated and defined to an extent permitting the development of guidelines for the project manager which can be universally applied with a given degree of certainty.
A four-phased life cycle concept is introduced, focusing on the pattern of manpower utilization. This is supported by (a) previously established management theory concepts, and (b) a twelve project sample-based survey.
The life cycle approach to project management views the whole project as a group of specialist functions (administration, design, production, etc.) or as a combination of resources (manpower, material, cash, etc.), each of which can be described in terms of its level of utilization (loading) throughout the project lifetime.
Life cycle approach material has been largely based on individual experiences or strictly theoretical hypotheses. For example, according to Stewart , “A project could typically be charted over time as a wave-like curve, rising gradually to a crest and dropping off abruptly with the accomplishment of the end result.” Cole, Bell, and Barrie , based on experiences at Kaiser Engineers, divided the project life cycle into three periods, Start, Run, and Stop. Project costs, according to Cole et al., seem to follow a bell-shaped pattern symmetrical around the Run period midpoint. A supplementary project pattern is suggested by Cole et al., estimating the degree of “mental anguish,” measured in ergs. This consists of two sharp peaks during the Start and Stop periods and a significant drop around the Run period midpoint.
A similarly qualitative approach was proposed by Bryson, Boal, Poole, and Terrell , who presented a six-phase descriptive for “program planning,” subject to six dimensions to determine the degree of innovativeness in each phase. The six phases were: initial response, initial feasibility study, plan development, pilot test, project development, and project transfer. Dimensions of innovativeness included: number of groups affected, number of sources of decision-making veto, visibility and controversy, technical difficulty, dollar cost, and time constraints.
Adams and Brandt  divided the project life cycle into four phases: Conceptual, Planning, Execution, and Termination. Based on field data gathered from program managers, organizational structure and behavioral characteristics were identified and measured for each of the four life cycle phases. Adams and Brandt's conclusions were that project organizations tend to be relatively small and exhibit the most favorable organizational climate in the early and late phases of their life cycle. They tend to become much larger and experience a less favorable (i.e., “mechanistic”) climate in their midphases. Other items evaluated by Adams and Brandt were level of bureaucracy, conflict intensity and sources, conflict resolution modes, and satisfaction.
According to Norden , the basic form of manpower distribution over time for projects consists of a rapid buildup to a certain peak, beyond which a relatively moderate manpower rate of decline takes place. This is expressed in the form of an exponential formula where the absolute values for buildup and decline rates are dependent on predetermined project duration and peak manpower loading. Norden arbitrarily selected a ±10 percent control interval around this formula and claimed some success in projecting manpower patterns at an IBM Development Laboratory.
The life cycle approach as a performance control tool is introduced by Mosgaard , who views a theoretical “trend curve” as the accumulation of individual project activities expressed in percent completed work as a function of time toward project completion. Horwitz  introduces project life cycle in the context of manpower budgeting procedures, where manpower employment schedule is drawn to reflect a preplanned project activity network. The AMTRAK case introduced by Egan  demonstrates a project life cycle presentation format used in monthly reports to provide visibility of key indicators of [a] performance system (KIPS) in a construction management process. AMTRAK uses a “six window format” to describe progress with time of six project variables, namely, cost, production, production rate, manpower, cost per unit, and forecasted variance. This can be used to evaluate single project progress as well as to compare progress among projects.
The uncertainties of predicting project life cycle patterns are dealt with by Carrier , who advocated the utilization of statistical techniques for more accurately determining project contingencies. In distinguishing between early and late project phases, he indicates the high uncertainty and variance associated with the former and the low uncertainty and variance associated with the latter.
The data utilized in the present study were extracted from a survey of twelve randomly selected completed projects. Information sources included personal interviews with key project personnel and project personnel records. The twelve projects, their implementation time frame, and information sources are summarized in Table 1. Raw data gathered included project manpower distribution over the period of project duration. Readings of manpower quantity were recorded at a constant frequency throughout project duration. That frequency varied from project to project, largely depending on project size in terms of total manpower employed and data availability. The data are summarized in Table 2. To permit project pattern comparisons independent of manpower quantity and project duration, these raw data were normalized as “percent of peak manpower” and “percent of project duration,” substituting for “man-months” and “months” units, respectively.
The project organization, like other business organizations, is viewed here as a network of positions with task assignments and their corresponding manpower skill prerequisites. These and the shape or structure of the organization produce a certain organizational behavior reflected by internal relationships, managerial style, decision making procedures, and subsequent performance level of the tasks. A distinction among four phases in a project “life cycle” is attempted here, and a discussion of each phase follows.
Phase I: This is a preparatory phase whose main task is the generation of new project ideas and initiatives. Personnel skill prerequisites here are similar to those frequently present in the work of R & D or consulting firms.
Perrow  describes this work type in a two dimensional framework as a combination of “many exceptions” (i.e., nonrepetitive work) and “unanalyzable search” (i.e., associated with unpredictable outcomes). Perrow's model describes the organization behavior that is called for here, as one that provides for high degrees of discretion and power at all hierarchical levels and groups inside the organization. This, in turn, produces high morale and satisfaction for the individual employee leading to organization-wide performance gains. Likert , for a similar organization type, introduces field data supportive of the “participative” rather than the “authoritative” system of organization structure. He views the organization as a network of small groups linked through overlapping membership to provide for information transmission and work coordination. Supervision in this structure emphasizes support rather than discipline of subordinates, producing high group autonomy and teamwork, discouraging a static, centralized leadership position in the group. These conditions lead to behavioral patterns which include: (a) the organization is unstable and evolves slowly; (b) high morale of group members; (c) an intensive occurrence and utilization of insight; (d) an increased number of performance errors in the short run; and (e) high performance in the long run .
In classical organizational structure terms, a Phase I organization can be envisioned as a “flat” pyramid, with large spans of control and a small number of hierarchical levels. Such structure, coupled with high task complexity, limits detailed supervisory intervention in subordinate work, producing autonomy, participative effort among peers, and other behavioral patterns as indicated above.
Project Sample Summary
|Project Number||Description||Information Sources||Dates|
|3||Consolidation of computer services in a corporation||Interviews with 3 managers, statistical records, monthly summary reports||6/67-12/74|
|4||Manufacturing and marketing of two sophisticated electronic products||Interviews with 5 top managers||1/69-12/78|
|5||Expansion of a trucking, cargo railroad, and warehousing enterprise||Interviews with executive vice-president and two staff members||1/73-1/78|
|6||Environmental control systems construction||Interviews with top managers and annual reports||1/69-12/77|
|7||Planning of long-range water resource utilization||Project organization record files||9/73-11/74|
|8||Major structural building remodeling||Company project record files||9/73-11/74|
|9||Structural design of a major subway station||Interviews with designers and supervisors, project documentation||9/74-2/77|
|10||Construction of a sulphur dioxide removal plant||Interviews with project managers and supervisors||4/75-2/78|
|12||Construction of a nuclear power plant||Interviews with managers and supervisors||6/69-6/76|
|14||Development of an electronic system for aircraft||Interviews with supervisory personnel||5/66-7/69|
|15||Design and construction of air pollution control equipment||Interviews with 4 managers, biweekly reports, cost sheets||1/73-3/77|
|16||Design of electrical and mechanical systems in construction||Interviews with managerial staff, accounting records||1/77-2/78|
Phase II: The major feature to distinguish between this and Phase I is the rapid organizational change called for here to comply with project execution needs. A preplanned sequence of activities dictates a compatible personnel recruitment pattern defined by specialist function expertise. The emerging organization can be described as a “composite” structure. This is a form of a socio-technical system constituting autonomous work teams of craftsmen at the “shop floor” level of the organization, subordinate to a single centralized authority of the plant . The organizational change, underlaid by a monotonic manpower increase, imposes costs as noted by Pfeffer , since “new roles must be learned, new patterns of interaction must be adapted, new tasks and relationships must be assumed”. In the project context, particularly as project duration increases, such costs become significant and predictability of manpower utilization patterns gains importance.
Survey results of eleven diverse projects are introduced in Table 3. A twelfth project (Project 9 in Table 2) is excluded from this analysis, since it was abruptly interrupted and later reactivated, causing irrational divergence from normal project pattern continuity. The data show regression and correlation results for Phase II, assuming advance knowledge of peak manpower employment and its time of occurrence, as indicated in Table 3. The data indicate that between starting point and peak manpower employment there is a 0.05 variance around a mean of 0.95 Man-Months/Month recruitment rate. In a supplemental analysis, similarly conducted, it was assumed that peak manpower employment is known in advance, but not its time of occurrence. Instead, advance knowledge of total project duration has been assumed. Thus, on a scale equating 100 percent with total project duration, the data demonstrate that between starting point and peak manpower employment there is a 0.22 variance around a mean of 1.32 Man-Months/Month recruitment rate. The confidence intervals and corresponding probabilities under both above circumstances are presented in Table 4.
Phase III: This phase is a steady state at peak manpower employment and resembles the common multifunctional organization of an assembly line. Management coordinates interfunctional operations, oriented toward the execution of clearly defined objectives. Standard procedures are established, including division of labor, hierarchy, and subsequent instructional information flows and feedback on performance. This calls for a relatively “tall” organizational pyramid, producing authoritative behavior across hierarchical levels, discouraging individual or group autonomy within the organization. Phase III duration, at its extremes, is either infinitely short under ideal project circumstances, or infinitely long if repetitive production remains desirable. When a prolonged Phase III is anticipated, the selection of an efficient organizational configuration becomes most important. Here, prescriptions for organizational design can be drawn based upon type of industry, technology employed by the organization, and surrounding socioeconomic conditions (   and others). This should lead to a steady state manpower composition by specialist function compatible with the various influences impinging upon the organization.
Field Data Summary
|Project Number||Number of Data Points||Duration (Months)||Peak Manpower (Man-Months)||Time to Peak Manpower (Months)||Total Manpower (Man-Months)|
Normalized Project Characteristics-Phase II
|Project Number||Data Points||Intercept (Man-Months)||Slope (Man-Months/Month)||Correlation Coefficient|
aTime units are percent time lapse between project start and peak manpower employment point.
bTime units are percent of total project duration.
Phase IV: Similar to Phase II, this final phase of the project involves rapid organizational change. A planned decrease in manpower is introduced here; and, based upon field data results presented in Table 5, this decrease appears to follow a higher change rate (averaging -0.98 Man-Months/Month) as compared with the corresponding change rate in Phase II (averaging 0.95). This can be expected on the grounds of better advance knowledge of the manpower needs pattern in a project termination phase as compared with the lesser knowledge associated with a project development and growth phase.
As in the case of Phase II, a supplemental analysis has been conducted here, assuming advance knowledge of peak manpower employment and total project duration (but not the time of peak manpower occurrence). Under these circumstances the data demonstrate that between peak manpower employment and project termination there is a 4.63 variance around a mean of -3.61 Man-Months/Month personnel discharge rate. The confidence intervals and associated probabilities under both of the above circumstances are presented in Table 6.
Similar to Phase II, the organization in Phase IV can be viewed as a “composite” structure  consisting of autonomous groups of specialists subject to centralized top project management. It should be noted that the small sample size (five projects) available for Phase IV prohibits conclusive results, but further study and expanded sampling seem worthwhile.
Conclusions and Recommendations for Further Research
The four-phase project life cycle concept discussed above is presented in Table 7.
The following observations are made:
(a) The project is divided into four phases; its personnel structure and behavior in each phase are described using organization theory terms.
(b) Organizational change is associated with Phases II (manpower increase) and IV (manpower decrease), while Phases I and III typically maintain a steady state.
(c) On the participative/authoritative continuum of organizational behavior, Phases I and III occupy opposite ends. While Phase I calls for the participative model, Phase III appears to adopt the more authoritive management style.
Regressions and Correlations - Phase II
|Interval (Mean ± 1 SD)a||-3.85 ± 12.45||0.95 ± 0.22||0.91 ± 0.14|
|Sample Based Probabilitya||0.64||0.91||0.91|
|Interval (Mean ± 1 SD)b||-3.05 ± 14.76||1.32 ± 0.47||0.91 ± 0.14|
|Sample Based Probabilityb||0.82||0.64||0.91|
aTime units are percentage of time lapse between project start and peak manpower employment.
bTime units are percentage of total project duration.
Normalized Project Characteristics-Phase IV
|Project Number||Data Points||Intercept (Man-Months)||Slope (Man-Months/Month)||Correlation Coefficient|
aTime units are percent of time lapse between peak manpower employment and project termination.
bTime units are percent of total project duration.
Regression and Correlation-Phase IV
|Interval (Mean ± 1 SD)a||94.44 ± 15.01||-0.98 ± 0.10||0.94 ± 0.05|
|Sample Based Probabilitya||0.80||0.80||0.60|
|Interval (Mean ± 1 SD)b||365.07 ± 211.16||-3.61 ± 2.15||0.94 ± 0.04|
|Sample Based Probabilityb||0.80||0.80||0.60|
aTime units are percentage of time lapse between peak manpower employment and project termination.
bTime units are percentage of total project duration.
4-Phase Project Management Pattern
|Task||Idea generation||Unit production||Assembly work||Unit finishing|
|Skill||R&D orientation||Specialist function expertise||Interfunctional knowledge||Specialist function expertise|
|Structure||Flat pyramid||Composite||Tall pyramid||Composite|
(d) Special managerial attention must be focused upon periods of transition between phases. The extent of individual and organization-wide adjustment called for is a function of project size, dispersion, duration, and other factors — all needing further research.
(e) In multi-project enterprises considering matrix-organization, prolonged Phases I and III would tend to adapt to a centrally based corporate control, whereas Phases II and IV would remain more highly decentralized and autonomous.
Forthcoming research and field studies are expected to investigate these and other observations.
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2. Bryson, J.M., Boal, J.M., Poole, S., & Terrell, C. A. Contingent Planning Model for Programs and Projects. Project Management Quarterly, 1979, 10, 19-29.
3. Carrier, K.C. Contingency, Project Management Quarterly, 1978, 9.
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5. Cole, V.E., Bell, W.B., & Barrie, D.S. Managing the Project in The State of the Art of Project Management, Project Management Institute, Northern California Chapter, 1977.
6. Egan, D.S., Jr. Key Indicators of Performance System (KIPS) Providing Visibility to the Construction Management Process in Proceedings of the Project Management Institute Seminar/Symposium, Atlanta, Georgia, 1979, 101-110.
7. Emery, F.E. & Trist, E.L. Socio-Technical Systems, in Systems Thinking, F.E. Emery (ed.), Penguin Books,
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9. Horwitz, E. Project Scheduling and Forecasting: A New Approach, in Proceedings of the Project Management Institute Seminar/Symposium, Atlanta, Georgia, 1979.
10. Likert, R. The Human Organization. New York-McGraw Hill Book Co., 1967.
11. Mosgaard, C. A System to Control the Implementation of Large Scale Projects, in Managing International Projects, Proceedings of the 5th International Expert Seminar, International Management Systems Association (INTERNET), 1977.
12. Norden, P.V. Useful Tools for Project Management in Management for Production, M.K. Starr (ed.), Penguin Modern Management Readings, 1970.
13. Perrow, C. Organizational Analysis: A Sociological View, Belmont, California: Wadsworth, 1970.
14. Pfeffer, J. Organizational Design, Arlington Heights, Illinois: AHM Publishing Corporation, 1978.
15. Rice, A.K. Productivity and Social Organization, The Ahmedabad Experiment, London: Tavistock Publications, 1958.
16. Stewart, J.M. Making Project Management Work, in Project Management, Edward W. Davis (ed.), 1976. Reprinted from Business Horizons, 1965.
17. Thompson, J.D. Organizations in Action, New York: McGraw Hill Book Co., 1967.
1This article is based on a paper presented in Boston, Massachusetts, and included in the 1981 PMI/INTERNET Joint Symposium Proceedings.
2 The author is indebted to the graduate students in the Project Management course at the Polytechnic Institute of New York during the 1978-79 academic year. Their participation in this research was of great value.