A must read blogpost

I was linked to this great blogpost "To my daughter's high school programming teacher, where a tech writer writes an open letter to her daughter's teacher, explaining how that teacher failed his duty to help foster an environment that welcomes young talented people, regardless of their gender.

The comments under the blogpost are unfortunately predictable - men denying the problem etc., so don't read them, unless you want to get annoyed.

Why you should allow your employees to go to conferences

A few days ago, I was talking with a friend, who I used to study together with. We were talking about GOTO Aarhus, and whether he thought he would be going this year.

He told me that it was unlikely, as the company he works for, has a limited training budget, which also covers conferences.

While I can understand why some companies might have to be careful about costs, it seems to me that this is short-term thinking, which will cost them in the long run.

In my experience, and in the experience of other people I have talked with about this subject, the people who ask for conferences, usually belongs to a group of people that the company would like to keep in their organization. This doesn't mean that the company wants to get rid of the people who don't ask for conferences. Rather, it means that innovation within the organization tends to happen from people who likes to seek inspiration everywhere (and what are conferences other than a giant source of inspiration?).

Conferences are, in other words, a great way to introduce new ideas and solutions into the organization, as long as someone who wants to go there, get to go. For the people going there, conferences are often a vital part of getting new ideas, since they will spending days together with like minded people, who might offer new insights. I think most of us have tried to hear someone say something, and suddenly have your brain go "click", realizing that you've dealt with a problem the wrong way. A conference offers you thousands of opportunities to get such "click" moments.

People like my friend, comes back from a conference with fresh new ideas, and new ways at looking at old problems, perhaps allowing for a novel new solution to a problem the organization has had for a long time.

So, all in all, my suggestion to companies would be, that if you have a employee who wants to go to a conference, think twice before saying no.

On the other hand, don't force employees to go. It is quite fine to suggest to someone that they go, but if they don't think that it's worth the time, it is pretty much a self-fulfilling prophecy, and a waste of money.

At the end of the post, I should probably also mention the fact that some people, myself included, consider conferences so essential that it is something we take into consideration in relationship to employment (my current employer, NineConsult, also considers conferences essential, so in that sense we're a good match).

This year's GOTO Aarhus conference

It looks like I might be going to the GOTO Aarhus conference again this year as a blogger, like I did last year. It is not completely decided yet, but there is a high likelihood.

If I am going, this would be 4th time I'm going to this particular conference, which is favorite conference (perhaps together with QCon London). Not that I have been to that many different conferences - I go to more than many people in IT, but I've only been to just over a handful of different conferences.

So, what am I looking forward to?

I haven't taken a full in depth look at the schedule yet, but glancing at the speakers list, I see several great speakers among them. People I'd hate to miss out of a general principle, would be Dan North, Jez Humble, Dave Thomas, and Ola Bini. Though I am considering Dan North, as I think I might have heard that talk before (I will have to hear the introduction to the talk).

I also noticed Kevlin Henney among the speakers, but unfortunately he is only there as a trainer for the training days. If you ever get the chance to hear him speak, I highly recommend it - he is an fantastic entertainer and teacher rolled into one.

Subject wise, I tend to avoid technology specific talks, and rather go for talks that can apply broadly across technologies. This means I have a tendency to go for talks related to processes, people, and principles across technologies (e.g. architecture or big data).

This year I think I will be spending my time mostly on the following tracks:
Monday: Architecture and "When the Agile Manifesto isn't enough"
Tuesday: "Lean IT Enterprise" - this is only half the day, so I need to find other stuff to fill it out.
Wednesday: "DevOps In Depth" and Career. Perhaps "Data in Reality", but there is so little information about the track right now, that I cannot really tell what the talks will be about.

The schedule can be found here

Another thing I am going to spend my time on at GOTO Aarhus is networking. I think it is incredible important to take advantage of the opportunity such a conference gives for meeting your peers and the masters of the field. And GOTO Aarhus is especially good at facilitating this, throughout the conference. I have been to other conferences, even other GOTO conferences, where this important aspect was lacking, but somehow GOTO Aarhus manages - especially during the conference party, where you have the chance to meet not only the other participants, but also the speakers.

So, if you're going to the conference, I highly recommend not missing out on the party. Who knows, you might end up having beer with someone like Michael Nygard or Jim Webber, both of which I have drunk beer with at conference parties. OK, probably not those two, as neither of them appear on the speaker list, but you get my point.

One should of course not forget to network with the vendors. People have a tendency to think that the vendors are just someone you should visit to get free stuff or win something, but this is a mistake. Often the people standing at the vendor booths are passionate about the company or product they represent, and they are often highly knowledgeable about the things they talk about. Remember, the vendors often send their best representatives to the conference in order to convince people.

A round-up of my GOTO Aarhus experience

Let's pretend for a moment that it is not nearly two weeks since I got back from GOTO Aarhus, and thus this blogpost really should have been written at least a week ago. Let's instead say that I've let my thoughts mature, before writing this blogpost.

No, the truth is that I've been busy both at work and in my private life, so I haven't really had the time to sit down before now, and put my thoughts into a blogpost.

So, what can I say about this years GOTO Aarhus conference? Well, first of all, it was awesome. Great speakers, great people. Just generally great. GOTO Aarhus is definitely still one of my favorite conferences, and they manage to get some amazingly inspiring people to come and talk. Among the speakers at GOTO Aarhus I'd definitely recommend other people to listen to, if they have the chance, are Jez Humble, Dan North, Linda Rising, Michael Nygard, Scott Hanselman, and Martin Fowler. Each of them are not only very knowledgable, but are also great at speaking.

Overall, the tracks were well thought out, and it seemed like there had been some thought given to who was invited (though I think the conference could have benefitted from a bit more focus on diversity, if possible). One thing I did find problematic though, was that the level of the talks were a bit too diverse, even within the same conference track - some were obviously aimed at beginners while others were aimed at more trained people.

That is actually one major criticism I have of the conference: They were not very good at indicating the level of the talk. Often you went to something which seemed interesting, and found out that the level was too basic for you to get anything out of it. This is something that the organizers should aim at improving.

Another point where the conference might be improved would be the agile track. The speakers there were generally great, and the subjects interesting, yet I couldn't help feeling that they were generally covering ground that had been convered many times before. Maybe it is time for an advanced agile track for those of us who have worked with agile for a while? I can't imagine that I am the only one who feels this way.

This was actually something they aimed at with the dev-ops track, and it seemed to me that this was a good approach.

So, what was the highlights for me?

The absolute highly must have been Dirk Duellmann's keynote about Distributed Data and Storage Management for the Large Hadron Collider. It was a facinating insight into problems the rest of us never faces (who else have to take the moon's orbit or the amount of rainfall into account when analyzing data? huge, huge amounts of data).

Other than that, a few other things stood out:

• The Ada Aarhus meeting, where Linda Rising gave a great talk, and Martin Fowler argued that quotas might be the only way to get more women into IT (he finds quotas problematic, but empirical evidence points towards them being the only options).
• Talking with the vendors. A lot of people going to conferences don't speak with vendors, and they are really cheating themselves.
• Listening to Dave Thomas explaining something about the problems he work with to Jim Webber.
• Catching up with friends and former colleagues and meeting new people.
• The noSQL panel, where bloated claims by noSQL vendors were talked about. Panels can be either dead boring or brilliant. Any panel which have both Jim Webber and Martin Fowler on it, is bound to be the latter.

As can probably be gleamed, I had a great time, and I am definitely looking forward to going there again. Still, as I said, I would love for better markings of the levels of the talks, and also for there to be an advanced agile track.

Sexism in IT, again

I'm currently at the GOTO conference in Aarhus, where I am spending a lovely time going to some great talks and meeting some great people, and I had planned on spending the evening blogging a bit about my impressions from the first couple of days at the conference.

Had.

That was until I had lunch with a couple of other people, and I heard about this incident (opens in a new window). Please go there and read the post.

As people who have been around me since I heard about this will attest, I've been pretty damn furious ever since first hearing about it, and then reading Cerian's blogpost (which was posted shortly after I heard about the episode).

I don't think I really have to explain why this incident makes me furious, but for good measure I will try to do so.

First of all, it is an incredible rude way to behave, and even if there were no other considerations, I think that unwarranted rudeness against complete strangers at a conference shouldn't happen.

But of course, it is not just the rudeness - it is the sexism that really gets me angry.

Can anyone even for a second imagine that a guy would have been addressed in that way? Yes, I am sure that there a few men who have been accused of being hired because of their looks, but it is not something people would say about a complete stranger that they had never met before, much less to that complete stranger. I mean, WTF? How can anyone think that it is OK?

Unfortunately, for women, this is a common remark, though not usually said directly to their face (though it happens all too frequently as well).

And it is not just men who makes this sort of remarks.

When we had a meetup of the bloggers/web media people before going to GOTO Aarhus, there was a woman among us who expressed her opinion that among the women studying Computer Science, there were two types:
1) The pretty ones, who got their (male) group members to do the work, and thus, couldn't code.
2) The non-pretty ones, who had to do their own work, and thus, could code.

In her mind, it was obviously not possible to be conventionally pretty, and be able to code.

I could now make some kind of argument about knowing pretty female programmers, but that would just be feeding the sexism. Rather, I'll just say that I cannot fathom why anyone would think it is acceptable to make that sort of comments, yet here there was a woman publicly stating these things. Among people she didn't know.

We seriously have a long way to go. A very long way.

Now, back to the incident. The thing that made me furious about the incident was not the fact that it happened (though that should be enough), but the fact that nobody spoke up when it happened. This is not mentioned in the blogpost about the incident, but I asked Cerian about it, and there wasn't. Or rather, one person said to her that she should ignore it, but nobody said anything to the guy about it.

The GOTO conference has an incredible good track record when it comes to not only getting female speakers, but also getting female attendees (once having to go to court for the right to give a discount to women in order to make the gender less underrepresented - a court battle they won). Yet, even at such a conference, not only does a guy feel entitled to make this sort of remarks, but nobody spoke out against him.

That shows me that the whole culture is still sexist at its core. Not that I think that the people who was there with Cerian are particularly sexist, or even that they agree with the guy, but I do think that they can't see how this sort of remarks are not only incredible hurtful towards Cerian, but also helps create an atmosphere where women, or a sub-group of women, don't feel welcome.

We, the IT sector as a whole, need to change that. Not only because it robs the sector of so much potential talent, but also because it is the decent thing to do.

So, if you see this sort of thing happening, speak up, and make clear that you don't find that sort of stuff acceptable. This is the only way to change the environment, and get rid of the sexism. We need to stop implicitly accepting this behavior by keeping quite, and instead explicitly express our disdain of it.

And it is important to note that it is extra important that we men are very active in doing this, showing our support in changing the environment.

On those words, I think I only have left to thank Cerian for speaking up, and that I hope that there will be some kind of official reaction from the GOTO conference. I know for sure that I will be following up on this issue, so expect more blogposts dealing with sexism, GOTO, and IT in general.

My schedule at GOTO

It is no secret that I love to go to conferences in general because it expands my horizonts and for the social aspects. However, in order to get the maximum enjoyment and value out of a conference, it is important that I go to the right sessions - both in the sense that I don't want to miss the good ones, and in the sense that I certainly want to avoid the bad ones.

I have been busy the last couple of weeks, so I haven't really had time to look at the GOTO schedule to see what sessions I want to go to. Still, looking at the program, I can see that there are certain sessions I don't want to miss, and certain sessions that I definitely want to miss.

So, how do I pick what sessions to go to?

Well, there are certain criterias:

• Who is the speaker?
• What is the subject?
• Is the session technology specific?

The first point should speak for itself. There are certain speakers I don't want to miss. People like Linda Rising, Dan North, Michael Nygard (all of whom have sessions at GOTO), Uncle Bob, and Kevlin Henney. This is the most important criteria for me, since I know going into their sessions that I will be challenged and get my horizonts broadened.

The subject of the session is of course also important. The subjects that interest me, are the ones with broader perspectives, rather than those focusing on narrow issues or technologies. Good examples of the sort of sessions I prefer are the ones in the Agile Perspectives, Continuous Delivery, Professional Productivity, or Humans at Work tracks.

And then there is the aspect of how technology specific the talk is. This is a criteria for choosing to not attend. In general I find that technology specific talks are a waste of time, unless they address a problem I am currently facing. And even when they address a current problem I am facing, I find that a bit of google searching will work just as well for me, and allow me to spend my time on a session which gives me more in the long run.

It should probably be mentioned that I am not very visual. Which means I prefer that people either tell me something, or hand me something I can read. This means that pictures, diagrams etc. are wasted on me, as are coding examples and demonstrations. Really, they are. When people start showing how to code something or other, I am bored to tears, and frequently have to fight the urge to fall asleep.

Since technology specific talks often contains loads of demonstrations, this might help explain why I usually find them a waste of time. Still, even if that wasn't the case, I think technology specific sessions are a clear case of wasted opportunity. How often have you come out of a tech specific session and brought something with you, which you can use even just two years later?

This doesn't mean that talks with code examples can't be good. At QCon London, Kevlin Henney gave a keynote talk on cool code (different version of the talk can be seen here), where he showed loads of code. That talk was brilliant, and I highly recommend watching the video linked above, even though it is a less energic version of the talk. It also provided great food for thought.

So, to sum it all up, I haven't really taken a deep look at the schedule for GOTO, but the tracks I have linked above will probably be where I spend most of my time, since they are the ones that provide most value in my opinion. One exception will be the time I spend at Dan North's HTML5 talk. It might be technology specific, but since it is Dan North talking, I know that I will be learning some new perspectives from it which I can use in the future.

Why go to conferences?

If people know me, it is no great secret that I am a great fan of going to conferences. Within the last year, I've been to several (GOTO Aarhus 2011, QCon London, QCon New York, and Community Day), and as I wrote in my last post, I'm going to GOTO again this year.

So, why do I love conferences so much?

Well, there are many aspects, but a lot of it boils down to two simple reasons:

• Expanding horizons
• Networking

Or to expand a bit more on it:

Expanding horizons: When working on projects on a daily basis, one tend to get bogged down on the problems there, and loose the greater overview. Going to conferences not only expands your knowledge, but also gives you new mental tools and frameworks to approach problems.

Heck, some times, the talks make you realize that you have been looking at the wrong problems all along.

Conferences are also great sources for inspiration towards improving yourself. E.g. at last years GOTO, Kevlin Henney gave a keynote talk on Cool Code which fired up just about everybody who listened to it (a video of a less energic version of the talk, which he gave at GeeCON can be seen here).

And of course, conferences help you keep track of tendencies and cool new technologies.

Networking: I am a quite social person (to put it mildly), and at conferences I get the chance to meet a lot of interesting people. The speakers are of course interesting to talk to, but the other participants are also frequently very interesting - the sort of people who wants to go to conferences are often opinionated and have interesting thoughts on many subjects.

So, if you go to conferences, remember to participate in the social events. Also, try to strike up a conversation with strangers, and see where that takes you. You'll often be positively surprised.

Going to the GOTO Aarhus conference

It turns out that I will be going to the GOTO conference in Aarhus this year in my capacity as a blogger. The kind people arranging the GOTO conference have invited me and some other bloggers to come along, and blog about the conference. I obviously thought this was a great idea, and thankfully my employers at NineConsult thought it was a great idea as well.

Since I am a great believer in full disclosure, I thought I'd better be upfront about this potential bias.

This will be the 3rd time I'm going to the GOTO conference - or rather, the second, as I've been once to GOTO and once to JAOO, which was the old name for the conference.

I can easily say that GOTO is my favorite conference - it has the right mix of talks about methods, technologies, frameworks, and broader developer-related subjects for it to appeal to me. It also has the advantage of not being wed to one specific technology - neither in talks nor in vendors. Another great thing about GOTO, is that the speakers are immensely approachable (to be fair, the same was the case at QCon London).

My blogging from the conference will probably be focused on two things:

1) Diversity,  or rather, how we get more diversity in our field, at our conferences etc. GOTO has been great in trying to increase the diversity both among speakers and among participants, and many of the people helping with GOTO are involved in great groups such as Ada Århus, which is a networking group for women in IT in Århus.
Those posts will probably be crossposted at my other blog, since this is a subject I discuss alot on that blog.

2) The talks. If there are some great or thought-provoking talks, I'll be sure to write about them. I've noticed that there is usually some kind of theme going through the talks (e.g. in QCon London in March, it was the concept of knowing your tradeoffs when making decisions), and I'll certainly make sure to write about any such at GOTO.
If any of the talks relate to error-driven development or how to end it, I'll of course also write something.

Reversed roles

Note: I should probably point out that in the following piece, I will follow the Danish tendency to not use peoples’ titles. For people not living in Denmark, this might seem disrespectful, and if it is perceived as such, I apologize, but the habit of not doing so is too ingrained in me, for me to start doing so now.

I was considering calling this piece “through the looking glass”, but that would have connotations of weirdness which I found inappropriate, since what I wanted to was to indicate that I had experienced the “other side” of the divide for once.

What divide you ask?

The gender divide. The gender divide in technology to be more specific.

People who have followed my other blog and twitter stream are probably aware that I am an out-and-open feminist, and that I regularly criticize my field (programming and IT consulting) for how women are marginalized, e.g. by the male dominance when speakers are picked for conferences.

This year I participated in such a conference; the GOTO conference in Aarhus, Denmark (the conference was formerly known as JAOO). Here the lineup of speakers was also heavily tilting towards men, but it is one of the conferences which actively tries to get female speakers, and they had managed to get some really great ones, including Linda Rising, Rebecca Parsons, and Telle Whitney.

Telle Whitney held a talk on women in IT, and all three of them participated in a meeting with the Ada Aarhus group, which was held after the talks on the second day of the conference.

I went to the talk, and participated in the Ada Aarhus meeting, and both of these things introduced me to the concept of being the outsider. Something which I understood, or at least thought I did, yet which I hadn’t really experienced before. I cant say I enjoyed the experience, but it was certainly enlightening, and it forced me to re-evaluate what I thought I understood on this subject.

Before going into how this happened, I want to back away a bit, and give a brief introduction to myself and that part of my background which is relevant.

First of all, as the sidebar says, I am a Danish IT consultant in my thirties. For those interested in the details, I am a .NET consultant, working mostly with large financial or public systems.

What the sidebar doesn’t mention, but which many people know, is that while I am Danish, I am also Australian. My mother was Australian, and while I grew up in Denmark, my childhood was a mixture of cultures - not only Danish and Australian, but also several others, since my childhood friends were also mostly of mixed backgrounds as well (though all with Western backgrounds).

This upbringing has left me unable to entirely relate to a typical Danish upbringing.

It is the small things that usually trips me up - the children's’ stories and songs that I haven’t heard, and the ones that I grew up with instead (would you believe that most Danish children don’t grow up with neither The Wizard of Oz nor Snugglepot and Cuddlepie?) - but it is also the inability of many to look beyond the borders, and think globally. The distrust of foreign things and multi-culturalism that people hold, thinking that anything foreign must be dangerous or less good.

This means that I am the outsider in some cases. But given that fact that I’ve grown up in Denmark not entirely so, and since I look Danish, I can always act in ways which allows me to fit in.

Going back to the woman in IT talk, Whitney talked about what companies and individuals could do to ensure women could advance in IT. A subject I feel strongly about. Yet when listening to the talk, I kept feeling that I was left out - that Whitney wasn’t talking neither to nor about me. The reason was that I am not in a position to make company decisions, and that the individuals that Whitney was talking to, about what they could do, was the women. Not the men. All the recommendations didn’t relate to me and daily life.

You know why? Because it wasn’t about me!

I knew this at an intellectual level. Yet I hadn’t realized the full impact until I experienced being left out. It bothered me more than I thought it would. My privilege kicked in, and I felt a bit of resentment at the gut level, while knowing fully well that this was how it ought to be, at the intellectual level.

If this was how I felt during a 50 minute talk, how must it not be for people who experience it day in and day out? E.g. women whose wishes and needs are ignored or LGBT people who live in a heteronormative society.

I cannot in any way pretend that I can relate to how they feel. But I can say that I understand it a little better now.

The Asa Aarhus group meeting, where both Linda Rising and Rebecca Parsons gave brilliant talks, just strengthening my understanding of this, and my realization of how little I can relate to how it would feel to experience this every day.

Hotfix Hell

I am a firm believer in many agile processes and tools, including iterative development, where you work with many deliveries. This allows for early, frequent feedback, and allows you to find errors early, before the project turns into an error-driven development project.

Unfortunately, this is not always possible.

A type of project I often work at, is the large project which spans several years, where the customer involvement is minimal, except at the start and at the end. This sort of project is pretty much doomed to go over time, go over cost, have many errors etc. They are exactly the reason why agile development has become so popular. Even if the project is developed agile, the lack of customer involvement, will mean that the project could in the wrong direction, without anyone finding out, before at the end.

Typical projects where this happens, are public projects subject to tenders. Here the scope of the functionality etc. is determined before the contractors bid on the contract (though often with a clarification phase at the start), and after the bid has been accepted (plus initial clarification phase has passed), the scope, deadline, and price are fixed. The customer will then often not be involved until the final acceptance test phase, where the solution is often found to be lacking (to put it mildly).

As this approach has obvious flaws, there has been an attempt to fix it by introducing sub-deliveries, which each has to pass the acceptance tests. In my experience, there are typically two sub-deliveries before the final delivery at the end.

This approach might seem somewhat agile, and since it gives earlier feedback, you’d think that it would help. Unfortunately, in my experience, it actually worsens the problem.

The problem is in the acceptance test part.

Picture the typical two year project with three deliveries (two sub deliveries and one final). Given the fact that there is a lot of scaffolding etc. at the start, the first sub delivery will fall after one year, with a sub delivery half a year later, and the final deliver half a year after the second sub delivery (i.e. one year after the first sub delivery).

This is, in itself, not an unreasonable schedule.

Unfortunately, the programmers involved will often have to acquire domain knowledge, while doing the scaffolding and early development of functionality, increasing the likelihood of wrong decisions and/or errors in the implementation. Some of this will become apparent as the first deadline approaches, and might be changed in time - unfortunately some it won’t be possible to change it all, and some misunderstandings will only become clear during the acceptance testing.

Since the project is on a tight schedule, the work on sub delivery two starts - often starting by changing the flaws found before the deadline, which they didn’t have time to fix, but also start on new functionality etc.

Unfortunately, the errors will still be in the code submitted to the acceptance test.

Since the errors are found, the acceptance test fails, and the customer rejects the sub delivery as it stands.

What happens then? Well, this is where the hotfix hell starts.

Given the fact that the code submitted as sub delivery one has failed the acceptance test, the developers have to fix the errors in the submitted code, which is now out of date, compared to the code base. This is done by making a patch or hotfix to the code.

The patched/hotfixed code is then re-submitted to acceptance testing.

If this passes, then all is well. Unfortunately that’s rarely the case. Instead, new errors will be found (perhaps introduced by the fix), which will need to be fixed, re-submitted, tested etc. This will take up considerable amounts of time, calender wise, but also resource wise - meaning that programmers, testers, customer testers etc. will use a lot of time fixing problems in the code, which they could have spent on other things. Other things, such as sub delivery two.

Just because sub delivery one has failed the acceptance test, doesn’t mean that work on sub delivery two has stopped - it is, after all, to be delivered six months down the line.

Unfortunately the plan didn’t take into account the hours need to work on sub delivery one after the delivery and/or date for expected acceptance test. This means that sub delivery two is in problems, since the developers won’t have time to do all the work required for it to pass acceptance test.

Meanwhile, sub delivery one and sub delivery two move more and more apart, resulting in developers having to fix problems in obsolete code - this is frustrating for the programmers, and introduces the risk of errors only being fixed in the old delivery instead of being fixed in both, since porting the fixes is difficult.

At some stage, the sub delivery will pass the acceptance test, or (more commonly in my experience) it will be dropped, as the next delivery either is about to be delivered or has been delivered.

Due to the work on the sub delivery one, the second sub delivery is unfortunately either late or in such a mess that it cannot pass acceptance test (or, more likely, both).

This means that when sub delivery two is handed in, hotfix hell starts all over again.

So, how can this be fixed?

Well, one way is to do iterations the agile way. Unfortunately, that’s not particularly likely to happen.

Another way is to base deliveries on the date when the acceptance test of the earlier sub delivery has passed. So in the above example, the second delivery will be handed in six months after the first delivery has passed the acceptance test.
Given the nature of the projects using sub deliveries, this is also unlikely to happen. Often the last deadline is defined by a new law or regulation, and is firm (until it becomes completely apparent that it cannot be done).

A more likely solution would be to take the overhead to hotfixes into account when planning. This would mean that the time spent on hotfixes on sub delivery one wouldn't take time set aside to sub delivery two. The problem with this approach would be that this would make the price higher when bidding, since more people would be needed to finish the work on time, than if one assumes that not hotfixes are necessary. On top of that, it is also hard to estimate just how much time is needed for this (in my experience, everybody vastly underestimates this).

My suggestion would be something more simple. Timebox the acceptance test - and call it something else.

Before the project starts, the customer and the contractor decide how much time will be used for testing the sub delivery in order to make sure that the fundamentals are fine, but without resulting in the developers having to fix obsolete problems.

When the timebox is done, the customer will either accept or reject - a rejection would mean that the customer think the code is so fundamentally flawed that it cannot be used. If that’s the case, the customer and the contractor will need to sit down together and figure out how to get on from there. Perhaps the final deadline will have to be moved, the contractor will have to add more people to the project in order to get it back on track, or the customer will have to become more involved in the development process (e.g. by providing people who can help testing during the development of sub delivery two).

I am well aware that my suggestion breaks with the concept of sub deliveries, but I would claim that the concept of sub deliveries is fundamentally flawed, and instead of helping a problem, it actually makes it worse. Since this is the case, I think we have to re-think how they are used, if at all.