How to Estimate Software Deliverables

When to give an error margin

➊ There's not enough requirements available.  

➋ You don't know enough about the deliverable solution.  

➌ You're unsure about impact on productivity when implementing new technologies.  

➍ It's in an unfamiliar business sector.  
 
 

Relative Estimation

Break deliverables into chunks and give the first section an estimate, and relative to how long the first section actually took, we can estimate further sections more accurately by using the first section as a known benchmark.  
 

Tips

 
◈ Take into account documenting/gathering/investigating requirements.  
 
◈ Make assumptions where requirements aren't so clear and illustrate this to the requirement gatherer so they can either accept your assumption (which will add uncertainty to your estimate), or ask for more in-depth requirements.  
 
◈ If there are 10 working days and you estimate it could take between 5 working days and 12 working days to complete the given deliverable, it's always better to be broad than narrow in your estimate because uncertainty will lead the inaccuracy of your estimate. Similarly, it's always better to overestimate and even then it probably won't be enough time.

September 12, 2020