Question

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What do I look for in a resume?

Answer

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Let’s start by the things I don’t look at in a resume for a position in which experience is expected:

• Your university: I couldn’t care less where you’ve studied. While having a university degree may sometimes tell me you’ve been serious enough to go through the pain of university, I also know it’s possible to go through university without acquiring any knowledge.
• Your grades: It’s great that you have A+ in so many classes. However grades do not always generalize to an effective worker. Furthermore, most of the applicants will also have high grades, which makes it a noisy/useless signal. Do understand that I also do not have the time to fact-check your grades, so you might as well have written you had a perfect score in every class. Be careful with this, as some people will see it as something to probe you on during the initial interviews, and this could backfire on you.
• Your extra-curricular activities: Unless you are doing extra-curricular activities that are relevant to the position you are applying for, I am not filtering for people with whom I could do things with outside of work.
• The list of all your publications: I work in a scientific field, and while for some publications are badges of success, I see listing articles as filler into a resume. If I want to know all the articles you’ve published, I can look it up on Google Scholar. Instead, focus on listing the areas of research you’re interested in and indicating how many papers in those areas you’ve published.

Here are the things I look for:

• 2-3 pages: If you cannot summarize your accomplishments in less than 3 pages, then you don’t know how to summarize. I don’t want to know everything you’ve done in your professional life. I don’t want to know every single paper you’ve published, every conference/workshop you’ve attended, every grant you’ve received, every honors you have.
• Relevant work experience: If you’ve been working in the same position for a different company, that will generally be a good thing. It means you already have prior experience in the field, you have seen how another company has accomplished what you might still do at your new job. It means you’ll be easier to ramp up and may require less supervision/support during that period.
• List what you did: If you only list the title/position you had and the company, I have no clue what you did there. You might as well not have worked there. Clearly list the big tasks/milestones you’ve worked on and what was your contribution.
• List clear and quantitative accomplishments: “Increased sales by 200%”, “Largely reduced operation costs” may sound great, but without the ability to compare against something, those accomplishments do not mean much.
• List technologies you’ve used: When hiring it is often common that you want your new recruits to already have some prior experience in the tools that are used at the company, especially if you need them to ramp up quickly. This is even more important when the set of tools used in your industry is common enough as it will communicate how in touch with the field you are.
• Proper ordering of the sections of your resume: It’s a little thing, but the ordering of the sections in your resume will communicate a lot to me. It will let me know whether you know how to prioritize, which is a critical skill. This point goes in hand with the “2-3 pages” item, as they both show that you are able to critically assess the content you produce.
• What you studied in university: I expect people that apply to the positions I filter for to belong into a certain set of domains. This is generally not a very important criterion, but it gives me a better idea of your professional career.
• When you finished your degree: This is used to determine how recent your education is. I consider professional experience once the degree is completed, not while it is being completed.
• Free of grammatical and syntactical errors: Make sure your resume doesn’t have major grammatical or syntactical mistakes. Those communicate a lack of seriousness and professionalism that I would expect in your future communication with others in the company. If your resume was initially written in a different language, make sure it is thoroughly translated.
• Github account: If you list one, expect me to look at it. If you don’t contribute much (less than 20 contributions per year), then it’s simply better not to list it.
• Personal website: If you list one, I will look at it as well. I have a background in web development, so I will use it as an additional way to evaluate it. Make sure it is online. A personal website that is down or for which the domain expired will lose you points.

Question

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What is data profiling?

Answer

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Data profiling is the process of extracting information about data. Given tabular data (think of an Excel spreadsheet), we commonly want to extract the following properties about each column:

• Number of rows
• Number of cells without data
• Number of cells with a value of zero
• Number of distinct/unique values
• Number of duplicate rows
• Minimum, mean, median, maximum, quantiles, range, standard deviation, variance, sum
• Values distribution
• Most common values
• Examples of values

The process of data profiling allows a data scientist or engineer to identify quickly potential sources of problems in the data such as:

• Negative numbers when numbers should all be positive
• Missing values which may need to be imputed or for which the row may have to be removed
• Issues with the distribution of values such as class imbalance if we plan to solve a classification problem

In an ideal situation, data profiling reports:

• No missing cells, this way you do not have to ask if data can be filled in or you don’t need to impute the data using assumptions
• Proper normalization of the data (e.g., value separate from their unit), this way the data can be used as-is, otherwise you need to transform the column to extract the numeric value from the unit
• All the data in a column using the same unit, unless otherwise specified (e.g., you do not want data in meters, centimeters, feet or inches in the same column), this way your data is consistent, otherwise you need to identify the scales/units used and transform the data to use a common unit
• Little to no row duplication, this way you know that your data was collected without creating duplicate entries, which sometimes happen when databases are merged manually to create a data file, otherwise you may have to drop the duplicate rows or identify how many of the duplicates should be kept

Question

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What are the general steps of a time series forecasting project?

Answer

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Data profiling

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Using a tool such as pandas-profiling, the dataset provided by the client is profiled and a variety of summary statistics produced, such as the min, mean, median, max, quartiles, number of samples, number of zeros, missing values, etc. are computed for numerical values. Other types of data also have their own set of properties computed.

These summary statistics allow you to quickly have a glance at the data. You will want to look for missing values to assess whether there’s a problem with the provided data. Sometimes missing data can imply that you should use the prior value that was set. Sometimes it means that the data isn’t available, which can be an issue and may require you to do some form of data imputation down the road.

Data analysis

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Common things to look for in time series data are gaps in data (periods where no data has been recorded), the trend/seasonality/residual decomposition per time series, the autocorrelation and partial autocorrelation plots, distribution of values grouped by a certain period (by month, by week, by day, by day of the week, by hour), line/scatter plots of values grouped by the same periods.

Data cleanup

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Data is rarely clean and ready to be consumed. This means many things: removing invalid values, converting invalid values or values out of range into a valid range, splitting cells that have multiple values in them into separate cells (e.g., “10 cm” split into “10” and “cm”).

Data transformation

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A variety of transformations can be applied to the cleaned data, ranging from data imputation (setting values where values are missing using available data), applying a function on the data, such as power, log or square root transform, differencing (computing the difference with the prior value), going from time zoned date time to timestamps, etc.

Feature generation

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Common feature generation transformations are applied, such as computing lagged values on variables, moving averages/median, exponential moving averages, extracting the latest min/max, counting the number of peaks encountered so far, etc. Feature generation is where you create additional information for your model to consume with the hope that it will provide it some signal it can make use of.

Establish a baseline

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Before attempting to find a good model for the problem at hand you want to start with simple/naive models. The time series naive model simply predicts the future by using the latest value as its prediction.

Experiment

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With a baseline established, you can now run a variety of experiments, which generally means trying different models on the same dataset while evaluating them the same way (same training/validation splits). In time series, we do cross-validation by creating a train/validation split where the validation split (i.e., the samples in the validation set) occurs temporally after the training split. The cross-validation split represents different points in time at which the models are trained and evaluated for their performance.

Performance analysis

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After you’ve completed a few experiments you’ll have a variety of results to analyze. You will want to look at your primary performance metric, which is generally defined as an error metric you are trying to minimize. Examples of error metrics are MAE, MSE, RMSE, MAPE, SMAPE, WAPE, MASE. Performance is evaluated on your validation data (out-of-sample) and lets you have an idea of how the model will perform on data it hasn’t seen during training, which closely replicates the situation you will encounter in production.

Model selection

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With many models and their respective primary metric computed, you can pick the one which has produced the lowest error on many cross-validation train/test splits.

Deployment

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Once the model has been selected, it is packaged to be deployed. This generally implies something as simple as pickling the model object and loading it in the remote environment so it can be used to do predictions.

There are two modes of forecasting:

• Offline: Data used for forecasting is collected during a period of time and then a scheduled task uses this newly available data to create new forecasts. This is generally used for systems with large amounts of data where the forecasts are not needed in real-time, such as forecasting tomorrow’s stock price, the minimum and maximum temperature, the volume of stocks that will be sold during the week, etc.
• Online: Data used for forecasting is given to the model and predictions are expected to be returned within a short time frame, on the order of less than a second to a minute.

Raw data is transformed and feature engineered, then given to the model to use to forecast.

Question

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Why should I write using simple, frequently used words?

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Using simple language will allow more people to understand your message.

Using simple words to explain ideas that are more involved makes it easier to understand those ideas.

It’s also easier to identify errors in reasoning when you’re expressing yourself with simple language.

Using rare words does not mean that you are more intelligent or have smart thoughts. It simply means you’re trying to conceal yourself by using words others may not understand.

Like writing software, you should aim to keep your writing simple. It makes it easier on the readers that don’t have to spend their time to understand what you’re trying to say.

Writing such articles is very difficult. For example, this article was written using only the 5000 most common words according to Wiktionary.

Question

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How is being a R&D developer different than being a developer?

Answer

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R&D developers are not focused on shipping. While most developers will work as hard as possible to ship whatever they are building to their customers so that they can get paid, R&D developers focus on delivering answers to questions asked by their clients. This focus on intangible deliverables will frustrate many developers.

Because R&D developers focus on answering questions and not building products, it is very common that code written will not make it in production. If it does, then it will generally be a catastrophe.

Code quality and maintenance are not considered a priority because code is expected to be abandoned once the questions have been answered and the solution has been proven useful.

R&D as it implies, is about finding solutions quickly to problems (research), building a solution (development) and demonstrating the value of the solution. This process is a lot more iterative than building software with (somewhat) clear requirements from the start. Given the novelty of what gets built, it is critical to get feedback early and to act on this feedback. This means that the development horizon (how far ahead things are planned) is very short. As such, you are unlikely to be able to say on what you will be working next month.

Regular development is about applying existing solutions to clients problems. R&D is about finding those solutions and turning them into mainstream solutions.

Question

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How can I effectively and consistently add habits into my life?

Answer

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I use the Loop Habit Tracker (an android app) to track any new habit I want to have and keep. Its purpose is two-fold: to remind me through notifications that I need to do something and to observe how consistent I am with the habit.

When adding new habits, I’ve found I was more successful by creating transition habits, that is, start with something that is easily achievable and is similar to the habit I want to have, then slowly transition the habit to be closer and closer to the habit I want to have. An example of this might be that I want to do 20 minutes of jogging daily, but since I’ve never done jogging consistently in the past, I should start with 1 minute instead of 20 and do it consistently. After a week of consistently jogging 1 minute per day, I can increase the habit to be 2 minutes. Each week that goes by the amount of jogging that is done is increasing while the habit is in its formation phase.

It may take up to 20 weeks to do 20 minutes consistently every day, which is preferable to me to trying to do 20 minutes of jogging right from the start and giving up after a few times because my body is not accustomed to such effort.

This same metaphor can be applied to mental efforts. If you’re not used to spending hours of focused effort on a task, trying to do it right away is likely to be very difficult. But if you slowly transition from doing none of it, to doing it a little bit, then more and more, until you reach your target, it will make something that initially appeared impossible manageable.

As you add more and more habits into your life, it may become difficult to keep doing all of them regularly without missing them. That is why an application such as Loop Habit Tracker will help you remember to do the habits you want to have.

Question

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Do you need a tech lead in your team?

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Let’s start with definitions of the tech lead role.

A Tech Lead is a software engineer, responsible for leading a development team, and responsible for the quality of its technical deliverables.

Source: https://www.thekua.com/atwork/2014/11/the-definition-of-a-tech-lead/

• Guiding the project technical vision;
• Analyzing risks and cross-functional requirements;
• Coaching less experienced people;
• Bridging communication between stakeholders and the team.

Source: http://vvgomes.com/we-dont-need-tech-leads/

• Lead with company values
• Deliver value to customers
• Keep the dream alive

Source: https://hackernoon.com/whats-the-role-of-a-tech-lead-7725b47104b7

I am of the opinion that the distribution of responsibility is likely the best way to get resilience in your system. But with it comes the cost of delays before eventual consistency.

Thus I am more likely to adopt a position where having or not a tech lead will depend on the situation of your team.

Do you need to make quick decisions? Either have a tech lead for that or limit the amount of time allocated for a group of individuals to make decisions.

Do you need accountability? Either have a tech lead that is accountable or have important decisions assessed as a group and the results of the decision written with the name of those that participated in that decision.

Do you need to have a technical vision? Either have a tech lead responsible for defining that vision with the team or have the team work as a whole to define this vision.

Tech leads should have a high-level overview of the pieces that need to be built and an idea of how to get there and when. As individuals, this would require coordinating between individuals with different opinions about those topics.

I work in AI, and this problem makes me think of having a single model (tech lead) vs an ensemble model (group of contributors). If your single model generally predicts the same thing your ensemble model would predict, then the single model is more efficient. On the other hand, if there’s no single model that can perform as well as the ensemble, then you should go with the ensemble model.

References

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• https://www.thekua.com/atwork/2014/11/the-definition-of-a-tech-lead/
• https://www.thekua.com/atwork/2015/06/tech-lead-circles-of-responsibility/
• https://www.thekua.com/atwork/2014/10/do-we-need-a-tech-lead/
• https://hackernoon.com/whats-the-role-of-a-tech-lead-7725b47104b7
• http://vvgomes.com/we-dont-need-tech-leads/

Question

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How do you document a process?

Answer

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A process is composed of a few things: inputs (dependencies), outputs and the steps to transform inputs into outputs.

Generally a new process will be created from a need (an output to be produced). For example, a client will come to you and ask to have software that does Y. Your output in this case as a software company is software that does Y. For the customer, the process they need you to develop is one where X (some unknown set of inputs) will be transformed to produce Y.

As a software developer, your task is two-fold.

First, you must develop a process for yourself to take client requirements (your input X) and convert them into software (your output Y), which means figuring out what needs to be done to go from X to Y (the transformation steps). Examples of those steps are requirements gathering, specification, design, architecture, implementation, testing, debugging, deployment, maintenance.

Second, you must develop a process for your client’s requirements, that is, one that converts some input information into their desired ability to produce Y. Examples of steps that would be in this process are uploading document A, B, C, processing the documents to extract specific information, produce report D.

When documenting processes, the steps will themselves become processes, that is, they will have a set of inputs and a set of outputs. A process will generally evolve into a complex graph of inputs, processes and outputs.

Processes are also generally accomplished by someone or something. In process modeling we refer to those as roles. Examples of roles are user, customer support agent, clerk, engineer, analyst, software system.

Here’s a very simple template that you can use to define your processes

• Inputs: What do you need for the process to take place?
• Processes: What actions are taken on the inputs to transform them into outputs?
• Outputs: What is produced when the process is completed?
• Roles: What roles are required to accomplish the actions of the process?
• Average duration: How long is a process taking to complete in general?
• Mandatory/Optional: Is this process mandatory or optional in the accomplishment of the higher-level process?

References

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• How do I improve my processes?

Question

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Given a library of processes, how can you determine which process you should be following?

Answer

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Make a list of all the processes you have. Link to all the procedures to follow in each case. Some processes you will use so frequently that you will learn them.

Processes have starting points, that is, a trigger that initiates them. For example, if you have a process for code reviews, the starting point is the creation of a pull request by someone else. Another trigger might be the beginning of a new project. You should look for and recognize those triggers. If possible, when you document your processes, indicate what will trigger the instantiation of one of these projects.

Try to frequently look at the list of triggers and think about what you are working on or will be working on. This will allow you to catch processes that should have been started and followed, as well as let you prepare for processes that are about to start.

As you accumulate more and more processes, you will observe that there is a hierarchical organization to them. As one process starts, you can already prepare a list of processes you may have to follow soon.

You will also observe that the completion of a process often will lead to the start of another one. Once you’ve established enough chains (sequences of processes), it will be easier to identify and do the processes.

References

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• How can I be systematic in applying processes?

Question

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What is the superficial loss rule applied to stocks and how does it impact me?

Answer

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The superficial loss rule states:

A superficial loss can occur when you dispose of capital property for a loss and both of the following conditions are met:

• You, or a person affiliated with you, buys, or has a right to buy, the same or identical property (called “substituted property”) during the period starting 30 calendar days before the sale and ending 30 calendar days after the sale.
• You, or a person affiliated with you, still owns, or has a right to buy, the substituted property 30 calendar days after the sale.

What this effectively does is that it prevents you from selling at a loss and rebuying the same stock within a 30 days period (before or after the transaction) for the purpose of tax harvesting during that year. This however does not prevent you from claiming the loss when you finally sell the stock.

It’s important to note that there is interactions between non-registered and registered accounts. Buying the stocks in one account and selling in another account will still be considered as if they were under the same account. The most important thing to understand is that if you have stocks in your registered accounts (TFSA/RRSP), that you buy/sell in these accounts within the 30 days window in a non-registered account, you will not be able to claim your adjusted cost base. This will result in a permanent loss of this taxable loss. As a simple advice, in other words, do not trade the stocks you have in your TFSA/RRSP in your non-registered accounts. It will simplify your life.

References

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• https://www.adjustedcostbase.ca/blog/what-is-the-superficial-loss-rule/
• https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/personal-income/line-127-capital-gains/capital-losses-deductions/what-a-superficial-loss.html
• https://canadiancouchpotato.com/2020/10/22/how-to-avoid-superficial-losses/