Different Approaches to Planning
Case Study – Travelling 15.000 kilometres in 23 days to Alaska by Car
The case study is about the process of planning a journey from Minneapolis to Alaska and back to Minneapolis by rental car in 23 days, which is a distance of more then 15.000 kilometres. When travelling such a long distance by car a lot of unforeseen things can happen: your car might have a flat tire, the road conditions might change due to bad weather or you just might discover a very beautiful place, which was not described in any travel guide and where you would like to spend some time. Further, there is no agreed upon or standardized way of how such a journey should look like, and the exact route might look quite different for every single traveller depending on her goals and her velocity.
This section illustrates the major differences of plan-driven, agile and chaotic approaches to software development on the basis of the Alaskan travel case study. We will accompany three couples on their journey: Paula and Peter taking the plan-driven approach, Alice and Andrew travellingagile and Christine and Charles preferring the chaotic approach.
Plan-Driven Planning Approach. Paula and Peter plan their journey using a pure plan-driven approach and fix the exact route before starting the journey. They read a couple of travel guides, browse the internet and talk with their colleagues to be well prepared for the journey. They estimate their speed based on previous experiences taking the type of roads (e.g., freeway or rural highways) into account. Paula and Peter further create a list of sights they want to see and they estimate the time needed to see each of them and the distances between them. They then calculate how far they can get on each day based on theses estimates. Thus, they came up with a proposed route and a detailed itinerary for each day of their trip. They discuss their plan with different people and adapt it to the feedback they obtain. Finally, they make reservations for all hotel rooms, campgrounds and shuttle buses and order tickets for a boat tour they want to take via the internet.
Agile Planning Approach. Alice and Andrew plan their journey in an agile way. Like Paula and Peter they spend significant time on preparing the travel and to get informed about the area. Alice and Andrew start out with a very high-level plan, which they refine over time as more information becomes available. They then compile a list of things they want to see during their journey and estimate and prioritize the items on the list. Based on this information they create a plan with a potential route and select potential places to stay overnight. In order to be flexible Alice and Andrew decide not to make all reservations in advance. Instead they look at the map and the places they might want to stay overnight and discuss about when the last responsible moment for making reservations would be. In case of high opportunity costs, for example, or scarce resources, for instance, they make reservations some time ahead, for all other cases they defer the decision as long as possible to keep their options open.
Chaotic Planning Approach. Christine and Charles do not like planning very much, instead they are in favour spontaneity and adventure. Therefore, Christine and Charles do not spend much time on planning and just make reservations for their flight to Minneapolis a couple of weeks before the journey to get a cheap fare. Except for this Christine and Charles do not make any plans and want to decide on-site what to do.
Alaska Supports Plan-Driven, Agile and Chaotic Planning Approaches
The Alaska simulator supports plan-driven, agile and chaotic planning approaches each of which takes completely different views on planning. The major differences of these approaches are summarized in Table 1. Both the plan-driven and the agile approach consider planning to be an essential activity, while chaotic approaches often lack a sufficient degree of planning and regard plans as unnecessary paperwork. In plan-driven approaches the planning is usually done at the beginning and is not a repeated effort like in agile approaches (cf. Fig. 1). Chaotic approaches either do not perform any planning activities at all or they perform them arbitrarily.
Although plan-driven and agile approaches recognize the value of planning, they have an entirely different perception of a plan. In plan-driven approaches a plan is viewed as a schema for execution. Instead, agile approaches use a plan rather like a guideline supporting decision making and recognize the fact that in dynamic environment plans are very often outdated and inaccurate. The famous quote of Dwight Eisenhower “in preparing for battle I have always found that plans are useless, but planning is indispensable” characterizes the agile perception of a plan very well (General Dwight D. Eisenhower). Further, both plan-driven and agile approaches have a fundamentally different strategy to deal with uncertainty. Plan-driven approaches try to deal with uncertainty by carefully planning everything upfront, which is only appropriate for processes which are close to both certainty and agreement. In contrast, agile approaches make decisions at the last responsible moment, which allows keeping options open and making decisions with the most information available (Mary and Tom Poppendieck 2006). Further, they plan for change and therefore make continuously investments to keep the cost of change low.
Table 1: Comparison of the Different Planning Approaches
|Total time spend on planning||High||High||Low|
|Time of planning||Beginning of project||During the entire project||Arbitrary time|
|Perception of a plan||Schema for execution||Guideline, help for decision making||Unnecessary paperwork|
|Strategies to deal with uncertainty||Careful upfront planning||Making decisions at the last responsible moment and reducing cost of change by planning for change||Spontaneity|
|Application area||Simple processes||Best suited for complex processes; can be applied to the entire process spectrum||Adventures|
To allow for all the above planning approaches the Alaska simulator provides two different simulation modes. First, there is the plan-driven mode requiring the traveller to completely specify the journey before its execution can start. Second, there is the agile mode, which gives the traveller more freedom and allows for a more iterative approach to planning. This mode allows travellers to spread the planning activities over the entire duration of the simulation. In principle, using this mode a traveller has all freedom in respect to planning is able to plan his journey either plan-driven (if all the planning is done before), chaotic (if no or only little planning is done) and agile (if planning is done iteratively).