What are the different methods of project estimation and when should you use them?

Project estimation is a critical part of any project management, it helping to determine the time, cost, and resources required . One of the method used in Petrochemical Industries -Small project is Bottom-Up Estimating: It Requires breaking down the project into smaller tasks and estimating the time and cost, Resources for each task individually. The estimates are then aggregated to provide an overall project estimate.

Estimate, Adapt, Succeed! ???? I'd emphasize the importance of context in choosing estimation methods. For early-stage, high-level planning, Top-down estimation is ideal. Bottom-up estimation is more detailed and perfect for well-defined projects. Analogous estimation, akin to a "comparative analysis," is proper when historical data is available. Using statistical modeling, parametric estimation is excellent for projects with quantifiable variables. Three-point estimation, inspired by the PERT (Program Evaluation and Review Technique) methodology, is best for projects with significant uncertainty. Each method has its place, aligning with the project's maturity, data availability, and required precision.

Project estimation methods include analogous estimation, parametric estimation, and three-point estimation. Analogous is quick but less accurate; parametric uses historical data for calculations; and three-point considers optimistic, pessimistic, and most likely scenarios. Choose based on project size, complexity, and available data for optimal accuracy.

Top-down estimation is an effective approach that begins by outlining a project's overarching scope and goals, then dissects these into smaller segments. It proves advantageous when there's a clear vision of the project's end result but lacks detailed task information. This method shines in providing swift, approximate estimates, securing funding, leveraging past project data, and expediting decision-making during initial project phases.

Adopt innovative approach, work with the team, be SMART in decisions, use collaborate approach, plan the work & work as per plan.

More accurate and detailed. Provide more realistic and better control of the project resources and schedule, but require more time to provide the estimation.

Bottom up estimation is recommended for detailed accuracy. Team members gain a deeper understanding of their tasks, fostering a more comprehensive comprehension of the project's scope and requirements. By breaking down the project, potential risks and challenges at the task level become more apparent, facilitating proactive risk management. However, some projects may have inherent complexities that are challenging to foresee at the task level, leading to potential underestimation of efforts.

Diese Art der Sch?tzung ist besonders bei sehr umfangreichen und komplexen Projekten ratsam. Gerade wenn viele Details und viele Akteure beteiligt sind, werden Controlling und Steuerung notwendig, um kritische Pfade und Abh?ngigkeiten zu identifizieren. Dies setzt gute Annahmen und klare Zielvorstellungen voraus. Durch die granularer Absch?tzung einzelner Ebenen, wird sie allerdings auch deutlich aufwendiger und zeitintensiver.

In summary, involves detailed analysis of each task or component in a project to create a comprehensive estimate. It enhances planing and control

En terme d'estimation de projet , celà dépends tout d'abord du nature de projet , et le choix de la méthode d'estimation doit être convenable au projet et il donne l'estimation exacte souhaité. A mon avis , j'ai géré assez de projet technique , les deux premières estimations descendante et ascendante sont les plus utilisés.

Analogous estimation relies on historical data from past projects that are similar in scope, complexity, and duration to the current project. This method is suitable when historical data is relevant and applicable to the current project.

It expertly breaks down the three-point estimation technique, offering a lucid understanding of its application in project management. The delineation of optimistic, pessimistic, and most likely scenarios underscores the method's nuanced approach to risk-adjusted estimates. The insightful emphasis on its relevance in high uncertainty settings, coupled with its adaptability to innovative projects and diverse teams, enhances its practicality in contemporary project environments. This comprehensive piece serves as a valuable guide for individuals seeking a nuanced comprehension and effective application of three-point estimation, especially in projects characterized by intricate risk profiles.

La estimación análoga puede proporcionar una estimación rápida y preliminar, especialmente al inicio de un proyecto cuando hay poca información disponible. Sin embargo, su precisión depende en gran medida de la similitud entre el proyecto actual y los proyectos anteriores utilizados como referencia.

Analogous estimation, similar to top-down estimation, is most effectively applied in the early stages of a project when comprehensive details are scarce. This estimation method is particularly suitable for projects with similarities in a fast-paced environment, offering a quick assessment based on past project resemblances. It proves valuable when swift decisions are required due to time constraints or when historical data for a specific project is limited.

Die analoge Sch?tzung ist eine hervorragende Erg?nzung zu allen anderen Methoden, da die Erfahrungen und Erkenntnisse vergangener und vergleichbarer Projekte, sowohl positive wie auch negative, mit einflie?en und somit die Sicherheit der Sch?tzung und somit der Projektumsetzung erh?ht.

In social work, analogous estimation proves beneficial when estimating projects with similarities to previous endeavors. Drawing on data from comparable initiatives in scope, complexity, and duration, this method is time-efficient and resource-friendly. It is particularly handy for simpler, standardized projects or when expertise and experience in the project domain are extensive. Analogous estimation allows social workers to quickly derive reliable estimates, especially when detailed assessments may be impractical due to limited resources or time constraints.

I never knew it had a name but I think this method is one that matches the approach needed in the contract furniture industry. It uses historical data from previous installations. I'm no math wiz but one thing I've actually found helpful is if you understand excel and creating spreadsheets you can actually keep your numbers better organized and create a sheet where you're just plugging in numbers. We've all seen the spreadsheets with large amounts of columns and rows and my approach is to "dumb" down the sheet and make it more readable and condensed. I would love to hear other people's approaches if this is similar to what your doing. After all the goal is to work smarter not harder.

Parametric estimation is suitable for projects with well-defined parameters and historical data available for model calibration. It is particularly effective for repetitive or standardized tasks where unit rates or productivity factors can be applied consistently.

With my proficiency in mathematical models and algorithms, I utilize parametric estimation to calculate estimates based on specific project parameters or variables. I apply this method when projects have well-defined parameters and historical data available for model calibration, allowing me to generate accurate estimates efficiently.

Parametric estimation involves using statistical relationships between historical data and other variables (parameters) to calculate project estimates. This method is beneficial when there is a strong correlation between the parameters and the project's scope. Real Story: In an automotive design project, parametric estimation was applied to estimate the time required for a new model development. The team used parameters such as the complexity of design features, the number of components, and historical data to develop a predictive model for time and resource estimation.

Three-point estimation involves considering optimistic, pessimistic, and most likely scenarios for each task and then calculating the expected value. This method is useful for mitigating uncertainties and risks associated with individual tasks. Real Story: In a research and development project for a pharmaceutical company, a three-point estimation was utilized to estimate the time required for the discovery phase. By considering optimistic scenarios where the research progresses smoothly, pessimistic scenarios involving unforeseen challenges, and most likely scenarios based on typical challenges, the project team created a more robust and realistic timeline.

PERT stands for Program Evaluation and Review Technique. It is a project management method that helps project managers estimate the time and resources required to complete a project. This method allows managers to plan, schedule, monitor, and control their projects more effectively. PERT is the use of three different time estimates for each activity: optimistic, most likely, and pessimistic. These estimates help managers understand the best and worst-case scenarios for each task, allowing them to make more informed decisions and manage their projects more efficiently.

I adopt three-point estimation by considering optimistic, pessimistic, and most likely scenarios for each estimate, enabling me to provide a more nuanced and realistic assessment of project outcomes. This method is invaluable when uncertainty is high, allowing me to account for variability and risk in project tasks and provide stakeholders with a comprehensive understanding of potential outcomes.

Three-point estimation is especially beneficial in: Risk Management: helps in identifying the range of possible outcomes and the associated risks. This is crucial for projects with high levels of uncertainty where conditions can change rapidly. Realistic Planning: The weighted average formula used in three-point estimation like PERT balances the optimistic, pessimistic, and most likely scenarios. This leads to a more balanced and realistic estimate than just using a single point estimate. Flexibility in Novel Projects: For innovative project, where historical data might be scarce or irrelevant, three-point estimation allows for a more informed guess based on expert opinion and scenario analysis.

The 3 E are very important points to be considered in a project. The optimistic, the pessimistic, the most likely estimate. All these scenarios must be taken into consideration when realizing a long term project.

Share your assumptions, explain your methodology, & manage expectations by highlighting the inherent uncertainty in any estimation. Track your progress, compare actuals to forecasts, & adjust your estimations as needed to stay on course. Adaptability is essential. Don't get discouraged by minor deviations. Use estimation errors as opportunities to learn, improve your techniques, & refine your planning skills. Involve stakeholders & team members in the estimation process, drawing upon their expertise & collective wisdom. Collaboration leads to better decisions. While data is valuable, don't discount your experience & instincts when making final estimation calls. A balanced approach leads to the most informed decisions.

The most important thing to realize upfront is the likelihood that the estimate you give is going to be considered. The most frustrating thing in estimation is wasted time. Know when to give a quick budgetary range and when to dig deep to give a valuable estimate. No half measures, no wasted time.

These types of estimation normally serve the business purpose and objective of the organization. Although unique with each other, the timing of implementation as well as the type of business concept / contract differs. For example, for a project without any FEED but the organization need to submit an estimate, there are a few concept that can be applied like Top-down & Analogous. For projects where there are already FEED and the information can be judged as sane for baselining, then the other estimation methods can be utilized. To simplify, the consideration varies and somehow subjective...

Delphi Technique: When to Use: When there is a need to gather expert opinions while maintaining anonymity. Description: Experts provide independent estimates, and a facilitator collects and summarizes the responses. The process is repeated until a consensus is reached. Vendor Bid Analysis: When to Use: When external vendors or contractors are involved. Description: Involves obtaining bids or quotes from potential vendors to estimate costs and timelines. This method is commonly used in procurement processes. Historical Information: When to Use: When historical data from previous projects is available. Description: Relies on data from similar past projects to estimate current project requirements. It helps in understanding patterns & trend

I carefully consider the unique characteristics and requirements of each project to select the most appropriate estimation method, ensuring that my estimates are accurate, reliable, and tailored to the project's specific needs.