Automating the Measurement of Heterogeneous Chatbot Designs (paper review)

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Paper from:

Using chatbots has gained importance in recent years, which has resulted in development of several chatbot platforms (like Amazon Lex, Google DialogFlow or IBM Watson). However, there is a limited number of studies related to quality assurance of chatbots. The paper from Pablo C. Cañizares, Sara Pérez-Soler, Esther Guerra and Juan de Lara addresses just this problem – how to guide testing of chatbots by using design metrics.

The paper proposes six global metrics (e.g., number of intents of the bot), eight intent metrics (e.g., number of training phrases per intent), three entity metrics (e.g., word length), and three flow metrics (e.g., conversation length). By measuring the values for these metrics, software designers of chatbots can predict three usability types – effectiveness, efficiency and satisfaction. To support the measurement process, the paper proposes a tool, available on GitHub, which can be used by practitioners. For some of the metrics, the tool employs machine learning and natural language processing. The metrics and the tool are evaluated on twelve chatbot designs. The tool could identify quality issues in terms of readability, conversation complexity, user experience and bot understanding. This demonstrates the usefulness of the tool in practice and how these metrics can help software developers in designing high-quality bots.

The metrics from the paper are:

  • INT – # intents
  • ENT – # user-defined entities
  • FLOW – # conversation entry points
  • PATH – # different conversation flow paths
  • CNF – # confusing phrases
  • SNT – # positive, neutral, negative output phrases
  • TPI – # training phrases per intent
  • WPTP – # words per training phrase
  • VPTP – # verbs per training phrase
  • PPTP – # parameters per training phrase
  • WPOP – # words per output phrase
  • VPOP – # verbs per output phrase
  • CPOP – # characters per output phrase
  • READ – reading time of the output phrases
  • LPE – # literals per entity
  • SPL – # synonyms per literal
  • WL – word length
  • FACT – # actions per flow
  • FPATH – # conversation flow paths
  • CL – conversation length

I will try to use these metrics if I write chatbot 🙂

Legacy code…

I stumbled across a great talk from Dylan Beattie about legacy code. It is a pre-pandemic talk, but it opens up with a great song and talks about legacy code differently than what we usually do.

There is a lot of great material and food for thought in this video, but I would like to turn your attention to minute 26, where Dylan talks about Excel and how the world runs on it.

He says that a lot of things are actually built on top of Excel because it is essentially a functional language of sorts. The software developed on top of Excel is also the software that is NOT written by professional programmers and software engineers. Yet, it is prevalent in modern society.

Don’t get me wrong. I am in favor of Excel. Love the tool and what Microsoft has done with it. It is so flexible that it can be used with almost all programming environments – from the built-in VBA (I know, ancient history), to Python or C#. We’ve done our share of Excel programming back in a day, e.g. designed measurement systems based on it: A framework for developing measurement systems and its industrial evaluation – ScienceDirect

I agree, the tool is not perfect, but it is installed on ALL office computers and can be executed by anybody. Just open up the file and run it. That’s why we chose it for the measurement systems. Well, at least until we had to do a big rewrite and go to SQL, dashboards, etc…

As I said – history.

Assessing the maturity of a metric team

MeTeaM – Metrics Team Maturity Model

Modern software development organizations work a lot with metrics – they use them to focus their development effort, to understand their products, and, recently, to guide their online experimentation.

We’ve studied software measurement programs before, mostly from the perspective of what’s in the program – what is measured, how it is measured, who is responsible for the measurement and when the measurement is conducted.

In this article, we focus on the “softer” aspects of the measurement program – how mature is a metric team, and how mature is the organization where the metric team works. When studying four different companies, aka four different teams, we could observe that the maturity of the team goes hand-in-hand with the maturity of the organization. Mature organizations can take metrics and indicators into their workflows, and therefore increase the motivation to learn in the metrics team.

We’ve also found a few key factors for success of the metric team:

  1. Formal, official mandate – which prevents questioning of the metric team, also important to make the team become a team, not a group of individuals
  2. Link to the organization – a team needs to be part of a product or service development, they need to understand what is required from them.
  3. Longevity – a team needs to be there for the long run, as the short term improvements will not last for very long (per definition), and therefore the motivation is not going to last.

I hope that this article, which is open access, will help others to understand how to evolve their teams and measurement programs.

Can we predict quality of service level quality based on metrics?

link to paper:

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Understanding how your product performs in the field is a very hot topic. To be honest, it’s always been. When we design and develop our product, we often want to know whether the outcome is going to be good or not. Well, this is not an easy task because we cannot really know to runtime properties of our products before very close to the final version. It’s difficult to measure end-to-end response time if we only have half of the database, or if we cannot simulate the full load of the product.

In this paper, the authors analysed over 700 web services and measured their code quality and interface quality as predictors for the quality of service.

From the abstract: source code and interface quality metrics/antipatterns are correlated with web service quality attributes (response time, availability, throughput, successability, reliability, compliance, best practices, latency, and documentation).

The internal code/interface quality measures were:

  • NPT: Number of port types, Interface
  • NOPT: Average number of operations in port types, Interface
  • NBS: Number of services, Interface
  • NIPT: Number of identical port types, Interface
  • NIOP: Number of identical operations, Interface
  • ALPS: Average length of port-types signature, Interface
  • AMTO: Average meaningful terms in operation names, Interface
  • AMTM: Average meaningful terms in message names, Interface
  • AMTMP: Average meaningful terms in message parts, Interface
  • AMTP: Average meaningful terms in port-type names, Interface
  • NOD: Number of operations declared, Code
  • NAOD: Number of accessor operations declared, Code
  • ANIPO: Average number of input parameters in operations, Code
  • ANOPO: Average number of output parameters in operations, Code
  • NOM: Number of messages, Code
  • NBE: Number of elements of the schemas, Code
  • NCT: Number of complex types, Code
  • NST: Number of primitive types, Code
  • NBB: Number of bindings, Code
  • NPM: Number of parts per message, Code
  • COH Cohesion: The degree of the functional relatedness of the operations of the service, Code
  • COU Coupling: A measure of the extent to which inter-dependencies exist between the service modules, Code
  • ALOS: Average length of operations signature, Code
  • ALMS: Average length of message signature, Code

This is quite a collection of measures and they are quite interesting, e.g. the average meaningful terms in port-type names. I must admit that it’s a new measure that I’ve not seen before.

The measures of the quality of service were:

  • Response Time: Time taken to send a request and receive a response, QoS
  • Availability: How often is the service available for consumption, QoS
  • Throughput: Total Number of invocations for a given period of time, QoS
  • Successability: Number of response / number of request messages, QoS
  • Reliability: Ratio of the number of error messages to total messages, QoS
  • Compliance: The extent to which a WSDL document follows WSDL specification, QoS
  • Best Practices: The extent to which a web service follows WS-I Basic Profile, QoS
  • Latency: Time taken for the server to process a given request, QoS
  • Documentation: Measure of documentation (i.e. description tags) in WSDL, QoS

Some of these are also quite interesting, e.g. Successability, which is the number of response messages per request messages.

The authors also measured some anti patterns of service design, which they list in the paper. I will not go through these anti-patterns, but I think that they are also correlated with some of the metrics.

I suggest this reading to everyone interested in web services and service design. Perhaps this could help us to get more high-performance services. I hope that I can see more of this type of research in the domain of service security – that’s an interesting area in itself.

Your code and AI – more than precision and recall!

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Using machine learning and AI to improve your coding is an important area of research. Together with colleagues we work with these techniques, to take them from open source to more industry quality.

There are two great tools that one can use today already. One of the tools is a beta version of add-in for visual studio, which helps software engineers to write code.

Microsoft is very active in this area and even has release a set of tools that support the development of AI systems:


What is great is that the tools are, naturally, available freely!

Another tool is a DeepCode, which analyzes software code and provides suggestions to improve it – e.g. use a specific design pattern or refactoring.

This is great that we have increasingly more tools and that AI engineering matures. We do not want to have precision and recall steer our development. We want to have real testing and real systems. We also need to work with data quality in order to ensure that the systems are reliable.

The alternative is that we use MCC, precision, recall, F1-score to tell us how good a system is, which is not entirely true. These measures do not provide any view on how the system reflects the requirements put on it. These measures allow us to compare different classifiers, but not systems.

I hope that we can focus more discussion on AI quality and not classification quality/accuracy.

Actionable software metrics – an interesting new article

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Working with metrics is a domain which calls for empirical data, which constantly changes. Software companies evolve and their metric programs evolve. I’ve always been interested how the metrics data is used in companies, especially in other geographical regions than the nordics. Although there are differences between companies in Sweden, Danmark or Finland, these companies are still more similar to each other than companies within the same domain in other parts of the world – and that’s perfectly fine.

In this paper, the authors captured my attention because they studied a few companies that were not on my radar before. The author have also found an interesting angle on the metrics work – what makes a metric actionable?

As it turns out, there are a few things that make the metrics actionable:

  • being practical
  • inform decision-making, and
  • exhibit data quality

These three characteristics are very important and agreed upon by most of the respondents. The authors also recognise the need of the metrics to be temporal, i.e. relevant for the information needs at hand.

What I also liked about the paper is that they provide the link to their data, which is the set of metrics used by the studied companies – a very interesting list:

However, what is interesting, and contradictory to what we have observed in our work, is the fact that the metrics which are focused on specific projects/products or universal, were not that popular. Instead, the metrics should be applicable for multiple products/projects, i.e. the type of the measured entity should contain more than one instance.

So, are the non-actionable metrics a complete waste of time then? Well, I would not say so. Neither do the authors. The non-actionable metrics can still be informative. They can be used to raise awareness of the issue, or simply provide the means for monitoring of the situation or the product, without the need to trigger specific decisions. Examples – product sales numbers, customer satisfaction, etc. Hard to act on them directly, but very important to collect and monitor.

Emerging new field – DUO – Data mining and optimization (EMSE article)

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New sub-areas or fields within software engineering are not that common, but they come up once in a while. The authors of this article (, Better software analytics via “DUO”: Data mining algorithms using/used-by optimizers) argue that this is the case now.

In this article, the authors provide a view that data mining and building optimization models are done in tandem and that this is the new field. They show that the data mined from repositories influences optimization models and that the development of models influences data mining.

The authors make the following claims (quoted from the paper, references removed):

  • Claim1:For software engineering tasks, optimization and data mining are very similar. Hence, it is natural and simple to combine the two methods.
  • Claim2:For software engineering tasks. optimizers can greatly improve data miners. A data miner’s default tuners can lead to sub-optimal performance. Automatic optimizers can find tunings that dramatically improve that performance.
  • Claim3:For software engineering tasks, data miners can greatly improve optimization. If a data miner groups together related items, an optimizer can explore and report conclusions that are general across a set of solutions. Further, optimization for SE problems can be very slow. But if that optimization executes over the groupings found by a data miner, that inference can terminate orders of magnitude faster.
  • Claim4:For software engineering tasks, data mining without optimization is not recommended. Conclusions reached from an unoptimized data miner can be changed, sometimes even dramatically improved, by running the same tuned learner on the same data. Researchers in data mining should, therefore, consider adding an optimization step to their analysis.

These claims make a lot of sense and they are aligned with my observations. I recommend this article for everyone who is working at or developing a metric team or a data analysis/data science team.

Testing ML applications

Image by Gordon Johnson from Pixabay


I’ve recently looked at the applications of different testing techniques for testing ML applications and got interested in the so called metamorphic testing. The idea is that we can check whether an output is within a specific range or set, which is called a metamorphic relation (

What is interesting about this paper is that it presents a framework for testing ML applications. I’ve not tried it yet, but I will as it seems very interesting to check how things work with this metamorphic testing and metamorphic relations. I’ve also interested in how to measure the quality of the software in this context.

Succeeding with large scale measurement programs

This week we had the possibility to give a webinar about how to work with large scale measurement programs. The webinar was dedicated for everyone who works with software metrics and would like to get more impact from that work.

It is not so much about the numbers, it is about the impact and what the numbers mean. The webinar that we present, provides a good understanding of how to make this impact. Based on our experiences, we chose all one needs to know to implement a measurement program in few weeks rather than years.

The webinar has been recorded and is available at this link:

Recording from the webinar about how to succeed with measurement programs.

Engineers and scientists love to measure. We measure complexity of software, its performance, size and maintainability (just to name a few). We need these measurements in order to construct software, manager organizations or release high quality, high reliable products. However, there is a difference between measuring software aspects and using the measures in decision processes. In this talk, we present the concept of measurement program, measurement system, information quality and indicator-triggered decisions. We show what to consider when setting up measurement programs and provide a hints about the costs and benefits of having the program. We end the talk with presenting recent research results from Software Center, where we combine measurements and machine learning to speed-up software development.

More materials about this are available here:

A while back we gave a webinar with a similar title, where we focused on the questions concerning the measurement infrastructure, visualization and assessment of the measurement program. The ACM webinar is presented here:

How do we know if something is popular…

Investigating diversity and impact of the popularity metrics for ranking software packages (review):

Image from Pixabay

I’ve written about the ways of assessing how good software is. One of the modern approaches, which I talked about before, is the use of A/B testing and online experiments. Providing the users with different versions of the features/systems/use cases allows the company to understand which of the options provides the best response from the users.

However, there are a number of challenges with this approach – the most prominent being the potential existence of confounding factors. Even if the results show a positive/negative response, we do not really know whether the response is not caused by something else (for example by users being tired, changes in the environment, etc.)

After using GitHub, both as a user and as a researcher, I sometimes wondered whether the star system is actually the right one. I wondered whether we should use a sort-of A/B testing system where we could check how often people usually access certain repositories.

In this paper, the authors take a look at different ways of assessing popularity of repositories. The results show that regardless of the metrics, the popular repositories are popular – i.e. popularity is not dependent of a metric.

Popularity metrics studied:

  • Total number of downloads of the package
  • Number of projects dependent on the package
  • Number of repositories dependent on the package
  • Source rank of the package
  • Number of forks
  • Number of watchers
  • Number of contributors
  • Number of stars
  • Number of open issues
  • Total number of tags

The actual analysis is quite interesting, so I recommend to take a look at the paper directly.