Monthly Archives: August 2009

6 Thinking Hats Retrospective Plan

I’ve done this one a couple of times now and had postive feedback both times. It’s a good alternative to the shuffling-cards-around-style retrospectives as it mostly involves talking (albeit in a controlled manner).

You can read about De Bono’s 6 Thinking Hats on Wikipedia where it is described as: “a thinking tool for group discussion and individual thinking. Combined with the idea of parallel thinking which is associated with it, it provides a means for groups to think together more effectively, and a means to plan thinking processes in a detailed and cohesive way”.


The description above sums it up and as I said it’s a good alternative format to more familiar plans

Length of time

Approximately one hour but can be tailored to your needs

Short Description

The team discuss the previous iteration whilst all wearing one of De Bono’s “hats”. They then do the same but wearing another hat until all the hats have been worn. The hats relate to particular ways of thinking and force the group to collectively think and discuss in a particular way. The facilitator documents any output on a whiteboard. The ouput from the last hat (Red) is converted into actions.


A large whiteboard and 6 coloured cards (one for each hat) and a room with space to arrange chairs in a circle (no table).



Arrange chairs in a circle so all the participants are facing each other. Put the colored cards along the top of the whiteboard in order of hat wearing (see below). Be familiar with all the “hats”.


Once everyone is seated introduce the exercise by giving a brief summary of De Bono’s Six Thinking Hats process. Then explain that the group will all put on the same hat and discuss the iteration (what went well, want didn’t go so well, what can we do to improve things) for 10 minutes and after that they will put on the next hat in the series and so on until the all the hats have been worn.

Very Important: If at anytime anyone starts talking in a manner not appropriate for the current hat interrupt the discussion and say something like: “That’s great Black Hat thinking, but we’re not wearing that hat right now. Remember, we’re wearing our Green Hats which are about alternatives and learning so please try to discuss the subject in this manner”.

Tip: The facilitator should try to stay out of the circle and try to avoud the participants talking directly to them. This is tricky as people have a habit of watching what you’re writing on the board. Try to block the board so they’re not distracted.

Order of hats

According to Wikipedia the order of hats most suited to process improvement is  Blue, White, White (Other peoples views), Yellow, Black, Green, Red, Blue but for this exercise we will use:

Blue, White, Yellow, Black, Green, Red

Blue Hat (5 minutes)

Use the blue hat to discuss the objectives for the session and write the output on the whiteboard.

White Hat (10 minutes)

Participants raise  and discuss anything from the last iteration which can be said to be a fact or information. Hunches and feelings and any discussion of reasons or other non information based output should be left for the appropriate hat.

Yellow Hat (10 minutes)

Participants can only talk about the good things that happened in the last iteration.

Black Hat (10 minutes)

Participants can only talk about the bad things that happened, any negative criticism they have or worst case scenarios they can think of.

Green Hat (10 minutes)

The discussion moves on to any ideas people have about solving problems or things that may add more value to the business or help in any way. Outside of the box helicopter view blue sky thinking is encouraged.

Red Hat (5 Minutes)

Give the participants a short period of time in which they can come up to the board and write down 2 emotive staments each. These could be the issues that have stood out for them the most or an idea for solving a problem. These statements should be instinctive which is why you will give them very little time to do this.

Conclusion and Actions

Spend a little time as a group having a look at the Red Hat output. Are there any themes? Do any of them have relationships to each other. Do any particularly stand out? From this get the group to decide on a couple of actions to take away. As always ensure the actions are very easy to execute (so nothing like “write more unit tests” or “refactor the database” and more like “try to write test first this iteration” and “arrange a meeting with the DBA to discuss a strategy for refactoring the database”).

How to initialise a class without calling the constructor (.Net)

Sometimes we want to test some really nasty legacy code but are inhibited by constructors taking tricky things like HttpWhatevers, God objects and so on which you do not care about but would require enormous effort setting up just to try and get an instance of the damn thing so you can test your method.

One way out is to create a parameterless constructor on the class which is only used for testing. Not at all nice, but sometimes necessary to create that first seam.

A candidate I was pair interviewing with introduced me to something which may prove preferable in these cases – the Microsoft serialization library has a method which will initialize a class without calling the constructor:


This way you don’t have to modify the code!

I would only ever advise using this if your only other sensible option would be to override the constructor. Hopefully once you have your tests you would be able to confidently refactor out the problematic code.

The same principles apply

The most obvious refactoring analogy I can think of is communal areas such as the kitchen of a shared flat. It’s everyone’s responsibility to keep it clean but often it quickly gets in a mess because people don’t bother to clean up after themselves. Sure, the cycle time to getting a meal may be quick, but after a while the kitchen becomes unusable. Finally a huge amount of effort has to be put in to cleaning it as some of the dirt such as on the cooker is really caked in by then. Other things are beyond cleaning have to be thrown away altogether.

Yesterday I spent a few minutes tidying the bookshelf at work. There was stuff on the shelves which shouldn’t have been there such as screws and mobile phone chargers ( commented out/redundant code), planning stuff spread across multiple shelves and mixed in with books (poor cohesion) and various colours and sizes of index cards in big unsorted piles (obfuscated unreadable code).

The same principles apply – leave it in a better condition than you found it. Be considerate of your colleagues and everyone benefits.

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Read books and earn more money

If I was going to offer one piece of advice to anyone aspiring to be a top class software developer* (apart from writing lots of code) it would be to read books. Not just any books though, books written by masters.

Experience often counts for little in software development. If you’ve spent your whole career in the same shop with little exposure to other languages or people outside your organisation it’s quite possible that some 21 year old upstart with a copy of Clean Code under his or her arm will wipe the floor with you when it comes to effectively writing and maintaining software.

Granted, working with good or even great developers will mean a lot will rub off on you. I’ve learnt countless lessons from the people I’ve worked with, but if I look around me people are no older than 30 at most with an average of around 5 years developing software in probably no more than 3 different organisations.

People like Martin Fowler, Eric Gamma, Kent Beck, Robert C Martin, Craig Larman and Michael Feathers have been at it for 25 years or more and in that time have slowly built up the kind of reputation you only get from regularly being right.

Also granted, blogs are are an invaluable resource, but are rarely little more then a meme in someone’s head and give you nothing like the deep contextual insight you can get from a well written book. There is also little to assure you that the author is anymore likely to have a better idea than yourself. Believe me when I say there are many people blogging who rarely live up to the practices they preach and are no more or less likely than you to know the right or wrong way of doing something.

I have learnt a lot from both colleagues and blogs, but both pale to what I’ve learnt from the books I’ve read. I can comfortably say there is no way I would be where I am today without them and I strongly believe it will earn you more money. When you think of all the things you could do to try and put more folding stuff in you’re back pocket it’s a relatively simple win!

I’ve been inspired to write this after reading Eric Evans Domain Driven Design which has gone right into my top 5 books of all time. Why is it so good? It’s not because Eric has necessarily been born with some supernatural instinct for writing great software or that Domain Driven Design is going to save the planet. It’s because it’s full of the lessons that Eric has learnt in his long and illustrious career, carefully woven into a highly readable narrative. There’s nothing particularly new here. Like all the great books I’ve read it is no more than a distillation of the practices in the industry which through time have proven to be the most effective. I remember Martin Fowler once saying that people often asked him what would be the future of software development. His answer was that to see the future you only have to look to the past.

Below is a list of the books which significantly changed the way I think and work more than any other’s I’ve read. No doubt you’ve heard of them all already and are on a list of books to read in the back of your mind somewhere and I’m sure there are plenty of others that had as significant an impact on people as these have on me. However I think few will argue that any of these books do not deserve their place on this list. All I can say is get on and read them if you haven’t already.

Refactoring: Improving the Design of Existing Code by Martin Fowler
Domain Driven Design: Tackling Conplexity in the Heart of Software by Eric Evans
Working Effectively with Legacy Code by Micheal Feathers
Agile Software Development: Principles, Patterns and Practices by Robert C Martin
Clean Code: A Handbook of Agile Software Crafstmanship by Robert C Martin
xUnit Test Patterns: Refactoring Test Code by Gerard Meszaros
Lean Software Development by Mary and Tom Poppendieck
The Toyota Way: 14 Management Principles from the World’s Greatest Manufacturer by Jeffry LIker

*I am in no way professing to be a top class developer 🙂