Monday, March 16, 2009

Story Dependencies

As I mentioned in this post, I am pretty annoyed with myself because of the way I structured stories in the first release of my current project. Here are a few things that I learnt.

First of all when we say that Story A is dependent on Story B, it means that Story B development cannot start until Story A development is complete

There are different situations where one story is dependent on another. Each situation needs to be dealt with in a different manner.

Types and Approaches

Situation 1 - The wrong split
This is the classic vertical split. Many have advised against it but many more fall into the same trap again and again. Myself included :)

Look out for the vertical split problem.
If your body is horizontally split in half as in you have no legs, you can still do something with yourself.

If your body is vertically split in half as in your left is separate from your right...

The first place to look for the vertical split is Admin Functionality / User side of the application. If you see your stories divided like Admin Stories and User Stories make as big a noise as you can quickly.

Situation 2 - The application flow
This is where we just plainly don't think.

When you get a message on Yammer, Yammer sends you an email. You can click on the email to look at the message you have got. BUT you can obviously keep your Yammer client open and see the message instantaneously and thats the way it's supposed to be used.

Email notification is a nicety. Showing the message on Yammer client DOES NOT depend on sending an email notification to the user.

Such errors are much easier to spot. Beware of the Business Process Workflows that you refer to. The business process workflow DOES NOT represent development flow. Mark the niceties and essentials apart in your workflow.

Situation 3 - Data dependence
This is a little more tricky. But I have seen this a lot of times as well. This is closer to David's comment on my earlier post.

Surely to sell an item, you need to set the item up in the system. Doesn't this mean that you have to build the Item CRUD features into the system before you can sell it.
Theoretically the items could be setup directly in the database. If the goal of the system is to sell an item, then that's what should be done first.

Practically you should be doing the absolute minimum "item setup" before you build the functionality to sell it.

The first thing is to concentrate on the crux of the system. Selling Stuff, Lending Books, Renting out DVDs, Playing Music, these are the things to achieve as early as possible in respective projects. Therefore you need to do whatever is needed to get to these areas as soon as possible.

I was mostly plagued by the admin V/s user situation throughout this release. We split stories that way because there was a tough deadline to meet and we thought it's better to split the work so that more pairs can work on the project. It worked out alright and we are in the last iteration and even able to provide a few more story points than promised. But we did face a lot of problems in scheduling because we split the stories in a wrong way. So that's definitely something to avoid.

Another thought that keeps popping in my head is the idea of Programming by Convention. Like RoR.

If you have a team of fairly experienced, "like minded" developers... can they agree upon a few conventions to follow so that two pairs can work on "Setting up the Item" (Admin part) and "Using the Item" (User part) simultaneously? I am still talking about evolutionary design (code as well as database). I seem to think that with good build processes, this should be possible.

What do you think?

Friday, March 6, 2009

Credit Cards, PCards and Level 3 data

Here's a post that talks about business more than business analysis.

I have been researching what it means to process level 3 data for credit cards. For quite a while now. Finally today I had that "Oh!" moment and I want to share it because I have had trouble finding data.

Credit Card processing is simple. I am assuming e-commerce here.

1. Customer enters credit card information (Number, expiry date, billing address, CVV)
2. Site (Merchant) sends the information to a CC processor.
3. CC processor talks to the issuing bank and authorizes the card
4. Site (Merchant) gets paid by issuing bank
5. Customer pays the issuing bank later

Not So Basics - PCards
Large Corporations and Government Agencies (LCGAs) realized one day that they could save a lot with electronic transactions and decided to use credit cards. But the employees went crazy with their personal credit cards. So Visa and MasterCard came out with special cards that were issued to employees specifically for official purchases. This is the Purchasing Card (PCard).

Level 3
However, the usual credit card transactions were difficult to settle. LCGAs realized that if the Merchant sent more data about the purchase to the CC processor while charging the card, LCGAs could get this data back from the CC Processor and thus could reconcile all transactions electronically and hence easily.

So the merchants started sending "Level 3" data to the CC processors. This is detailed data about the line items for which the card is being charged.

The basic benefit of Level 3 data is that LCGAs can reconcile the purchases made by their employees easily. They can also keep a check on what the employees are buying.

Level 3 processing is only beneficial for PCards. Not for consumer Credit Cards. It's advisable for merchants to pass Level 3 data to CC processors because it increases their chance of working for LCGAs as well as gets them some discount on transaction processing fees.