After an hour spent working through the stand-alone functionality of the LM kit in small groups everyone gathered again.
“We’ve got a new story to add,” said Alan. “During the spike and after doing some research we found some existing 5 step exercises which are already written and fairly easy to do.”
“And our group,” added Amir, “thought the Try Me submenu was worth treating as a full exercise.”
“Yes,” said Alan, “we thought so too, perfect for Primary Level.”The extra story cards were added to the list.
“What we’re going to do,” Mary started, “is estimate the stories using ‘story points.’”
“What’s a story point?” asked Daniel.
“A story point is a unit-less measure of size and complexity for a story, we’ll think about duration after we’ve got a feel for size and complexity.”
“Shouldn’t I be thinking in terms of how long it’ll take?” said Daniel.
“Not yet,” said May, “this way we’ll get a general feel for the size and difficulty of the story before we get into the detail.”
“The devil is in the detail,” said Daniel.
“Yes,” replied Mary, “but this will also help us understand what these stories actually mean before go to that level of detail. Now we’ve added the extra stories after the spike.” (Table 4)Table 4. Primary Level User Exercise Stories
Story Text | Estimate |
|---|---|
As a student I want an opportunity to explore the Try Me submenu. (&View submenu) | 0.5 |
As a student I want to make my robot drive faster so that it wins the race. (Robot Rally Race) | 3 |
As a teacher I want the student to apply maths concepts to driving the robot. | Relegated to common task. |
As a student I want to build the basic driving base | 3 |
As a student I want to make the robot go back and forth when its Touch Sensor is pressed. | .5 |
As a student I want my robot drive and turn when I clap my hands. | .5 |
As a student I want my robot to drive along until it detects a dark floor colour. | .5 |
As a student I want my robot to move forward, whistle a tune and wait for its touch sensor to be pressed. | 1 |
As a pupil I want the robot to respond to sensor input so that it behaves differently. | 1 |
As a pupil I want to modify my robot to make it better than the other groups’ robot. | 1 |
As a student I want my robot to speak when I clap my hands. | .5 |
As a teacher I want to demonstrate how logical steps create the robot’s behaviour | 2 |
As a teacher I want the students to connect and operate sensors and motors. (NXT Program submenu) | 1 |
“We should size the stories next,” said Mary. “We’ll be using the story points I talked about before, remember this is just to get a general feel for the size and difficulty of the story before we talk about how long it will take. We’re going to estimate by playing ‘planning poker.’”
“What’s planning poker?” asked Daniel.
“It’s an estimation technique that gets over the problem of people anchoring their estimates based on each others, you know, when the first person picks a number out of the air, and you go along with it just because it’s out there,” said Mary. Each of you takes 7 index cards and writes your own deck of numbers on the back, lets say: 0, 0.5, 1, 2, 3, 5, 10”
Yi spoke up, “because we’re simply developing supporting material for an existing product we thought the estimates would be thought of in range of hours and fractions of hours.”
Mary continued, “but the point is to get an estimate of size rather than how long it will actually take. But, yes, our starting assumption is notionally to use hours, however if you think days or weeks are required then say so. Anything less than half an hour we’ll treat as 0. And before anything else, keep your estimate secret until I ask you to show your cards. Shall we start with the first story, the Try Me submenu?”
“OK,” said Mary, “has everyone selected a poker card? Right, let’s turn them over.”Alan and Daniel both estimated 0; Amir and Paraic 1; Mary, Stewart, Yi and Neal 0.5.
“Not too extreme a spread,” said Mary. “Alan and Daniel, why zero?”
“Well,” said Alan, “it seemed a pretty trivial exercise, definitely less than half an hour of ideal time.”
Mary asked, “Amir, what were you thinking about for the ‘Try Me’ exercise?”
“Well,” began Amir, “Quite simple really, instructions for students to wire up the brick, then each student should get a hold of it and run through the options, there were 5 options if I recall correctly. We’d need to document the learning goals, some pointers on what to do if students delete the tests. That kind of thing.”
Neal added “That description ties in nicely with the programme. It seems the sort of thing that should be done with both user groups, Primary and Secondary.”
“So,” Alan began, “you’re saying our job is to write up a crib sheet or instructions to the teacher to deliver this story?”
“Yes,” said Neal, “our job is to provide other programmers and engineers like ourselves with the cheat sheets and scripts to run these exercises in classroom settings. Think of the situation we’ll find ourselves in; 25 or 30 students in groups of 5 or 6, following your instructions, Lego bricks scattered on tables. This programme is going to need to be pretty well bulletproof. Even a simple exercise like this one can quickly unravel into chaos in a classroom setting.”
“Shall we do another round on this story?” asked Mary?Everyone agreed. This time the estimates were: Daniel still 0; Alan, Amir, Paraic, Mary, Stewart, Yi and Neal 0.5.
“Well Daniel,” asked Mary, “would you be prepared to see it estimated at 0.5 rather than 0?”
“That’s OK with me,” said Daniel.
“Right,” said Mary, “let’s move on. Making my Robot faster”
“This story isn’t meaningful,” said Amir, “it needs a concrete example before it can be performed. You can only make the robot faster to win a race if the exercise involves a driving robot and a race of some sort. And the third story, well all the exercises will typically involve some maths concepts, this story is so general that it could apply to everything.”
“One at a time,” said Mary, “so you think the second story isn’t clear, it should be a race exercise or competition of some sort?” Everyone agreed so Mary updated the card. “And the third card, isn’t a standalone exercise, you think it is a feature or task for all exercise stories?”
“Yes,” said Amir, “that makes it sense.”
“So what we’ve done here is clarified the definition of story 2, and relegated story 3 into a general task for the exercises,” said Mary. “Can someone update the ‘exercise’ stories, on the other side of the card write ‘maths concepts described.’”
“Just a thought,” said Alan, “should our estimate for Try Me story be updated to account for this?”Mary asked if anyone thought the estimate needed revision but no one did.
“OK,” said Mary, “this story, build the basic driving base.”
“This one is a problem!” said Daniel. “First it has nothing to do with programming, but you can’t do anything useful until you’ve got it done.”
“There’s nothing wrong with it not being programming,” said Stewart, “hardware is important too.”
“Right,” said Daniel “but this exercise is really time consuming and requires a lot of concentration. Primary Level students just may not get it done in time. It took me nearly an hour. It’s fiddly work. Can you image a group of 6 or 7 ten year olds working together under time pressure?”
“All right,” continued Stewart, but we’re not estimating how long the students will take to complete the exercise, we’re estimating how complex it is to document it as an exercise in ‘Cool.’”
“I’m just saying it’s by far the most complex exercise on the list. And by the way, it needs to be done to before the interesting 5 step programming exercises can be done.”
“Do we have enough information to estimate?” asked Mary? “Right, ready? Show your hands.”This time the estimates were: Daniel, Alan, Amir, Paraic, Mary, Stewart, Yi and Neal 3.
They continued planning poker estimation of the rest of the stories until they reached the final one.
Stewart spoke up. “I think the first and the last stories are duplicates. After having used the NXT brick I think the Try Me submenu does both of those things.”
“But,” Yi added, “the view menu also give access to some of that functionality as does the NXT Program submenu.”
“Perhaps we can treat them as separate exercises?” suggested Alan, “Try Me is quick and easy, whereas View gives a quite ‘technical’ view of the sensors, even motors as sensors with rotation detection. I can see quite a lot of learning objectives being covered just using ‘View.’”
“Well, OK,” conceded Stewart, “you’ve convinced me, perhaps we should add View to the first and clarify the last stating it should deal with the NXT Program submenu?”There were no objections so the story cards were updated and the estimate played.
NEXT STAGE >>
