The statement accurately describes the genesis of the Bureau-Shaping Model. To understand this, it's essential to first grasp the Budget-Maximizing Model, primarily associated with William Niskanen, and then see how Patrick Dunleavy's Bureau-Shaping Model emerged as a critique and refinement.

The Budget-Maximizing Model (Niskanen): William Niskanen's model, developed in the 1970s, posits that bureaucrats, like actors in other organizations, are rational utility maximizers. However, unlike private sector actors who might maximize profit, Niskanen argued that bureaucrats primarily seek to maximize their bureau's budget. A larger budget, in this view, translates into greater power, prestige, higher salaries, more perquisites, and increased opportunities for promotion for the bureau chief and staff. Niskanen suggested that bureaucrats exploit their informational advantage over politicians (who are the 'sponsors' of the bureau) to secure budgets larger than what would be socially optimal, leading to an oversupply of public goods and services.

Critiques and the Rise of the Bureau-Shaping Model (Dunleavy): While Niskanen's model offered a powerful, albeit cynical, explanation for bureaucratic behavior, it faced several criticisms. Critics argued that not all bureaucrats are solely driven by budget maximization, and that the model oversimplifies the complex motivations within public administration. It also didn't adequately differentiate between various types of bureaus or the career paths of different bureaucrats.

Patrick Dunleavy's Bureau-Shaping Model, developed in the 1990s, emerged as a direct response to these limitations. Dunleavy argued that Niskanen's model was too simplistic and that bureaucrats are more sophisticated in their utility maximization. Instead of maximizing the total budget of their bureau, Dunleavy proposed that senior bureaucrats (especially those in 'top-level' or 'core' bureaus) are more interested in maximizing their discretionary budget and the size and prestige of their policy-making functions, rather than the overall operational budget.

Key tenets of the Bureau-Shaping Model:

1. Focus on Discretionary Budgets: Senior bureaucrats are more concerned with the parts of the budget they can control and that enhance their influence, such as policy development, strategic planning, and external relations. They are less interested in 'running costs' or 'output budgets' for routine service delivery, which might be delegated or contracted out.
2. Minimizing 'Running Costs': To free up resources for their preferred activities, senior bureaucrats might actively seek to 'shed' or 'contract out' routine service delivery functions (e.g., payroll, IT support, direct service provision). This reduces the 'running costs' of their core bureau, allowing them to focus on more prestigious policy-making roles.
3. Career Path and Prestige: Bureaucrats are motivated by career advancement, which is often tied to involvement in high-profile policy areas, strategic decision-making, and managing external relationships, rather than simply overseeing large operational budgets.
4. Differentiation of Bureaus: Dunleavy recognized that different types of bureaus (e.g., 'top-level' policy bureaus vs. 'delivery' bureaus) would have different motivations. The bureau-shaping dynamic is more pronounced in core policy-making departments.

In essence, the Bureau-Shaping Model refines Niskanen's theory by suggesting a more nuanced and sophisticated form of bureaucratic self-interest. Instead of a crude desire for a larger overall budget, Dunleavy argued that senior bureaucrats strategically 'shape' their bureaus to maximize their personal influence, policy impact, and career prospects by focusing on core policy functions and shedding less prestigious operational tasks. This makes it a more realistic and empirically robust explanation of bureaucratic behavior in modern public administration, particularly in the context of New Public Management reforms that emphasize contracting out and efficiency.