ISS brief by AIR 20 Archana Shukla

Indian Statistical Services (ISS)

The best thing about being a Statistician is that you can optimally analyze yourself.



Why this blog?

During my preparation, I felt a dearth of Online guiding resources for this exam. How to start preparation, what to cover and what not, always remain a question of concern. More than the resources, it took me three years to understand the nature and demand of the exam.

Here, I have tried to give answers to some of the possible queries. As this exam consists of two parts – Written and Interview, First I discussed how to start the journey, along with my strategy and resources for all the papers separately. After taking a bit about the Notes Making strategy and approach to study, I shared about the interview preparation in the last.

Hope it helps!


About Me   

Hi, my name is Archana Shukla and I have secured Rank 20 in the Indian Statistical Service Examination 2020 with God’s grace and the immense Contribution of My Family, Mentor, and Friends. This was my third attempt.

I am a resident of village Maigalganj belonging to district Lakhimpur Kheri, Uttar Pradesh.

I completed my Graduation with the subjects Statistics and Computer Science from Mahila Vidyalaya Degree College, . Thereafter, I pursued my Post Graduation in Applied Statistics from Babasaheb Bhimrao Ambedkar University, Lucknow.

After completing post-graduation, I started preparing for the Indian Statistical Services Examination.

Here is the Mark sheet of my final attempt –

How to start the journey

Starting the preparation can be a bit Confusing and tiresome without any guiding path.

Here are some steps to make your path easier -

·       First ask yourself Why do you want to join the Indian Statistical Services? Are you interested in the working profile of the job?

·       Second step is to get well acquainted with the syllabus and Examination Pattern. Analyze your base (On Which topics do you have a good command and which you have not studied even once) Highlight the important topics in the syllabus regarding their weightage of questions asked in the PYQ’s. It will help you to analyze the level from where you need to start your preparation.

·       Third step is to collect all resources for study (also from your B.Sc. or M.Sc. level notes if any)

·       Last but not least, prepare yourself mentally for the upcoming Roller coaster phases during your preparation. Be Disciplined, make a routine and have Patience as it will take some time to bear the fruits. Strategize your preparation from the macro to micro-level.


Detailed Strategy for Written Part 

General Studies and General English Preparation of these two papers is much correlated. You can’t prepare for these two papers overnight. You have to gradually develop an understanding of the current issues and their history.

General Studies

·       Current Affairs -

1.     Vision IAS Monthly Magazine - Highlight content while reading so that you can revise it easily (avoid unimportant international news)

2.     Daily news analysis – You can watch Editorial analysis on the channel BYJUS, Only IAS, or can read the newspaper and understand the issue by yourself (Try to read the editorials as much as possible, in case you can’t understand it, refer to any news analysis)

It will help you to build up your views on any topic. If you want to make any notes from daily news analysis, wait till any current topic concludes.

·       Polity-

1.     I referred to the YouTube lectures of Veer Talyan Sir on the channel Study lover.

You can study from M Laxmikant Book. I studied only Important things (related to current affairs and PYQ’s) for a general understanding.

While answer writing, Focus on PYQ’s and try to write all answers in one place for quick revision.

·       History –

1.     I referred to the Modern part only from the book “Spectrum’s A brief history of Modern India”.

I focused only on the topic asked in the PYQ’s, studied the book only as a reference.

·       Geography and Economy Section –

1.       I referred to Current Affairs only for these sections.

·       Answer writing practice –

1.     I used the Insight IAS app. Must start answer writing 3-4 months before the exam.

I also downloaded the Answer copy of IAS Anudeep Durishetty Sir to see the answer writing pattern.

General English

·       Precis Writing

1.       I Refer to the

·       Essay writing –

2.      I refer to the essay strategy of IAS Saurabh Sabhlok Sir (available on YouTube) and IAS Anudeep Durishetty Sir (downloaded the Anudeep sir test copies to see the essay pattern)

3.      Newspaper reading will make you content-rich for the essay.

4.      I made a possible list of topics for the Essay by analyzing PYQ’s and Current Issues.

5.     I noted down some quotes by famous personalities on the possible essay topics like Women, reservation, Education, etc. for the Essay.

·       English Grammar part –

1.     Book “Plinth to paramount” by Neetu Singh.

I noted down previous year Idioms and phrases with their meaning in one place to get an idea about it.

·   Practiced a good number of Essays, Precis, and Paragraph writing from PYQ’s. Note down idioms and phrases, words, and titles of paragraph writing from PYQ’s in one place. It will help you to understand the meaning and further practice.


Booklist for Statistics Papers

Statistics Paper I

·       Probability

1.     a. Fundamentals of Mathematical Statistics Volume -I by S.C. Gupta and V.K. Kapoor

b. Statistical Inference by George Casella and Roger L. Berger

c. An Introduction to Probability and Statistics by Vijay K. Rohatgi and  A.K. Md. Ehsanes Saleh.

2.     Decide chapters as per the syllabus, I studied Gupta Kapoor as the base book and the other two books only as a reference i.e. go through the chapters once and check if any different kind of example is there.

3.    The order of the books is according to their requirement i.e. First study Fundamentals of Mathematical Statistics Volume -I completely, only then look for the Casella Berger and Rohatgi for further mathematical details.

·       Statistical Methods

1.     Fundamentals of Mathematical Statistics Volume -I by S.C. Gupta and V.K. Kapoor (for Non-parametric methods – I took help from Online resources)

      You can also refer to the Fundamentals of Statistics Volume I by Goon, Gupta, and Dasgupta for graphical methods.

·       Numerical Analysis

1.     Finite Difference and Numerical Analysis by H.C. Saxena.

·       Computer application and Data processing

1.     Computer Fundamentals by Pradeep K Sinha and Priti Sinha.

2.    Search topics from the syllabus on the internet and write down factual information from PYQ’s if any.

·       Previous year question paper

1.     ISS, IIT -Jam, GATE, CSIR, IAS (Objective paper -2009,2010) (for IIT JAM solutions, you can refer to the book “Solutions to IIT JAM for Mathematical Statistics by Amit Kumar Misra and Mohd. Arshad”)

2.     You don’t need to solve all the papers of other examinations properly but you must take an idea about how a concept can be asked in different ways. (Choose questions corresponding to the syllabus and approach for this exam)



Statistics Paper II

·       Statistical Inference and Hypothesis Testing

1.     a. Fundamentals of Mathematical Statistics Volume -I by S.C. Gupta and V.K. Kapoor,

b. Statistical Inference by George Casella and Roger L. Berger,

c. An Introduction to Probability and Statistics by Vijay K. Rohatgi and A.K.  Md. Ehsanes Saleh.

2.     Decide chapters as per the Syllabus. I used Gupta Kapoor and Casella Berger as the base books and the Rohatgi as a reference.

3.    The order of the books is according to their requirement i.e. First study Fundamentals of Mathematical Statistics Volume -I completely, only then look for the Casella Berger and Rohatgi for further mathematical details.

4.    for Bayesian inference, I took help from Online Resources.

·       Linear Models –

1.     Linear estimation – “Linear Estimation and Design of Experiments by D.D. Joshi”- up to chapter 4.

2.     One-way and Two-way classification – “Fundamentals of Mathematical Statistics Volume -II by S.C. Gupta and V.K. Kapoor”

3.   Linear Regression - Shalabh Sir notes( initial chapters)

4.   Linear Models by S.R. Searle (Chapter 1,2,3 and partially chapter 5) for inverse and full rank model.

5.     for Multiple comparison tests - Internet and PYQ’s

·       Official statistics –

1.     MOSPI website, Online Resources. (focus on the structure and working of the official Statistics, released reports by MOSPI, etc) 

·       Previous year question paper-

1.     ISS, IIT -Jam, GATE, CSIR NET, IAS (Objective paper-2009,2010)

2.     It is not necessary that you solve properly all the papers of other examinations but you must take an idea about how a concept can be asked in different ways. (Choose questions corresponding to the syllabus and approach for this exam)

Statistics Paper III

·       Sampling

1.     a. Theory and Analysis of Sample Survey Design by Daroga Singh,

b. Shalabh Sir notes,

c. Sampling Theory and Methods by S. Sampath.

2.     I Studied Theory and Analysis of Sample Survey Design by Daroga Singh and Shalabh Sir notes as a base and S. Sampath book as a reference.

3.    The order of the books is according to their requirement i.e. First study Theory and Analysis of Sample Survey Design and Shalabh Sir notes completely, only then look for the S. Sampath book.

·       Econometrics

1.    a. Basic Econometrics by Damodar N Gujarati (choose chapters as per the syllabus and PYQ’s),

b. Shalabh Sir notes.

·       Applied Statistics

1.    Fundamentals of Mathematical Statistics Volume -II by S.C. Gupta and V.K. Kapoor.

2.    Time Series Modern part – “Introduction to time series and forecasting” by Peter J. Brockwell and Richard A Davis.

I studied the book only as a reference for understanding, along with the online resources. (I did not prepare this topic deeply, just took an idea for concepts and numerical)

·       Previous year Question Paper-

1.     ISS, IAS, RBI

2.     It is not necessary that you solve properly all the papers of other examinations but you must have an idea about how a concept can be asked in different versions. (Choose questions corresponding to the syllabus and approach for ISS exam)

·       Compare and choose the questions that you can write well in section B of Paper III


Statistics Paper IV

·       Multivariate –

1.     a. Applied Multivariate Statistical Analysis by R. A. Johnson and D.W. Wichern,

b. An Introduction to Multivariate Statistical Analysis by T. W. Anderson.

c. Follow the book according to the topics. First, go for the book by Johnson, and then if needed, look for the book by Anderson. You can also watch the YouTube lectures of Prof Amit Mitra as per your availability of time and understanding.

·       Demography 

1.     Fundamentals of Mathematical Statistics Volume -II by S.C. Gupta and V.K. Kapoor.

2.     Online Resources for the unavailable topics in the book.

3.     Dr. Tanujit Chakraborty Sir Demography notes (                                                          

·       Previous year Question Paper –

1.     ISS, IAS, RBI

2.     It is not necessary that you solve properly all the papers of other examinations but you must have an idea about how a concept can be asked in different versions. (Choose questions corresponding to the syllabus and approach for ISS exam)

3.     Analyze the Multivariate section of paper IV- 2020, you will get to know the importance of solving question papers of other examinations (especially those conducted by UPSC)

4.     Compare and choose the questions that you can write well in section B of Paper IV 

How to Study – 

Before jumping straight to the Study, Analysis and planning are a must to do. 

The first step is to analyze which means to take an overview of the Syllabus and PYQ’s and find out the topics and approach to study.

The second step is planning.  Plan from macro to micro level. Like if you have a whole year, assign initial months for reading and note-making, the rest months for the mock test, and revision. Now plan for a specific month, week, and day. Remember that your planning must include some margin time and it must be doable for you. The revision target should be daily, weekly, monthly, and tri-monthly. Don’t ignore the weightage of GS and GE paper in your planning (Study GS daily and GE weekly)

Now to prepare the Statistics papers, I have divided my studies into three rounds –

                     1. Reading

Collect all the resources for the topic you are going to prepare. Understand the concept, solve examples and unsolved questions. Along with Keep analyzing the PYQ’s to know the approach and weightage of topic in the paper.

                     2. Notes Making

Prepare the notes according to your understanding and focus on keywords. For Descriptive papers, try to concise your notes with every revision as you need to revise a large syllabus in 2-3 hours on the day of your exam. For effective revision, you need a handwritten note in a very concise way (e.g. the whole sampling part in a 3-4 A4 size sheet) The Continuous cycle of Mock test and revision will provide you an understanding of what to write and what not in your notes.

Moreover, since you do not have any answer key for papers III and IV, prepare a model answer copy year-wise or topic-wise yourself. It will save your time when you check your mock answer copy.

                    3.  Mock Test –

First attempt for the portion-wise mock test with timer. It will help you to analyze the possible mistakes topic-wise e.g. In the case of Paper I, first attempt separately for Probability and Statistical Methods, Numerical Analysis, and Computer Application. Paper I consists of 80 questions - 40 questions from Probability and Statistical methods, 20 questions from Numerical Analysis, and 20 from Computer Application. So while opting for Numerical Analysis, if time exceeds more than 40 minutes, take a look and see how you can limit it to 40 minutes.

Similarly, you can attempt the other two portions of a paper I. After the Mock test, analyze your mistakes and find out the reason behind them. The possible reasons can be - You have not understood the concept well, or you are doing any calculation mistakes, are unable to remember the specific formulas, or not reading the question attentively. Try to work on your mistakes and improve every time.

After a portion-wise mock test, attempt for a complete mock test and analyze whether you are able to maintain consistency continuously for two or three hours as per the paper. Again Analyze your mistakes and work on them.

Answer Writing – While Answer writing in papers III and IV, Consider these two points-

·   Write a precise answer (only the things that have been asked)

·   If you don’t know the answer completely, try to write as much as you know accurately.


How to attempt the paper – 

Before one or two days of your exam, relax physically and mentally. Don’t try to revise anything as you will be unable to remember because of the anxiety and nervousness of the exam. Arrange your bag, pen kit with all the essentials.

During those three days, remember the following things-

·       Be optimistic and believe in yourself, you have worked very hard throughout the year, now it’s time to execute.

·       Have a light lunch during the gap period of two papers and keep yourself hydrated. keep fruits, dark chocolate in your bag.

·       Don’t discuss your performance of any paper in the gap period of two papers.  Remember, every paper is an opportunity, in case any paper has gone beyond your expectation, think about it after you have performed your best in all possible opportunities.

·       Proper sleep is mandatory for your brain to recall the answers.

       To attempt Objective Paper, divide it into three rounds-

·       In the First round, solve the questions you know with 100% accuracy, fill the OMR sheet.

·       In the second round, solve the questions which can be done either with smart guessing or through elimination, again fill the OMR sheet.

·       In the last, try for questions that you don’t know at all.

·       You can circle and double circle for the identification of questions assigned for the second and third rounds. In case you got stuck in any questions, don’t waste your time and move to the next question. 

For Descriptive Paper, Choose the questions carefully in section B and try to write them precisely. Your writing should be readable, don’t waste your time decorating your answers so much. Try to attempt the questions to the greatest degree possible.


Notes Making Strategy

It seems tiresome and unnecessary to maintain notes but remember, it will be very fruitful when you revise the whole syllabus. I advise preparing notes as per your need and understanding. e.g. In case you have M Laxmikant’s book and you are comfortable revising from the book only, then you can just highlight the important topics and revise. There is no need to consume your time in notes making.

·       To Prepare notes for a topic, First understand the concept and then Identify the approach for making notes with the help of PYQ’s.

·       In case there is any fact or any new topic has been asked in the PYQ’s, note it down and go through it later.

·       Once you are in the revision mode, try to concise your notes during revisions as per the need for quick revision.

·       Write each piece of information as per your understanding (focus on keywords) and revise it 4-5 times.



First, I will discuss the preparation of the Interview and then discuss my experience in a nutshell.

·       Detailed Application Form - Fill the details carefully and frame questions yourself about you, your hometown, your college, etc. basically each minor detail filled in the DAF

·       Statistics - Cover up your basics well including Official Statistics. Focus primarily on the reports released by MOSPI and figure out which statistical concepts have been used e.g. Systematic sampling, PPS Sampling, etc.

·       Current affairs - Focus majorly on the issues related to the economy. You can watch the Big picture show on RSTV. Try to think of your role as a UPSC aspirant, more like as a Statistician to resolve the issues.

·       Mock interviews – Work on your Communication skill and build up your confidence. Learn how to deal with questions you don’t know. (To the best of my knowledge, no coaching center provide the facility of mock interviews so you can practice for mock interviews with your friends and mentor’s help) 

·       My Experience – My Interview experience was wonderful. I worked on my DAF questions well (I majorly focused on my hobby too but no questions were asked about it). Apart from that, I tried to work on my Communication Skill and body language. My interview was conducted in the Afternoon session of 20 July 2021 at UPSC Bhavan, Dholpur House, New Delhi. As I entered the Premises, I need to complete formalities regarding document verification. Then as per my time, One Assistant came and took me to the Interview Hall.  The Interview panel consists of 4 members including the Chairperson Dr. TCA Anant (Former Chief Statistician of India). After greeting the panel members, I was offered to take my seat and my interview began. Here I have listed some Questions based on my memory. You can get an idea here. (Avoid questions that are directly from my background)

1.       Introduce yourself.

2.       Which discipline of statistics do you like and why?

3.       Which statistic you will use to reach any conclusion in the testing of the hypothesis.

4.       What is the p-value?

5.       What is the difference between one-tailed and two-tailed tests?

6.       What is the difference between a statistic and a parameter?

(Question number 7-12 are from my DAF)

7.       What is the contribution of Babasaheb Bhimrao Ambedkar? In UP, do you think marginalized sections have been given required privileges?

8.       What is disaster management?

9.       Which authority (particularly department) is there for disaster management?

10.   What is the cycle for disaster management?

11.   What have you learned from NSS camping and scout guides?

12.   What have you learned from the workshop on data analytics on R? 

13.   If you have been given a chance to make India equivalent to a developed country, what will you do?

14.   What do you mean by Education (This question is related to the previous answer)

15.   What can be your role as a Statistician in this case.

 The interview is a personality test. It requires you to be presentable with knowledge. Hence try to identify your weak points regarding communication and work on them.



Some Key Tips


·       In this Exam, you have 6 papers to score well, so identify your strength and work on your weakness. e.g., If GS preparation looks tricky and time-consuming, you can aim to clear the cutoff and devote the rest of your time to other papers in which you can score well.  

·       Stick to the resources once chosen for study. Don’t go overboard.

·       Focus on syllabus and more importantly PYQ’s to study any topic. e.g. in the case of Econometrics, you can avoid K Class estimators or 3 SLS estimators as it has not been asked even once.

·       Try to attempt maximum questions in Paper III and IV. (I had attempted almost 80% of paper III this year but did not get expected marks. So try to attempt as much as possible accurately.)

·       Hard work (with smart work), Patience, and Perseverance are the Key.

·       You have to maintain your Physical and Mental health to execute your hard work on D-Day. So, while making your Routine, remember that it should be doable with small study breaks.

·       Don’t compare yourself to others. You may come with a different base in this journey, but there is always a chance to learn.

·       Try to simulate the examination environment at your place while giving mocks. If possible, simulate a 3-day Mock test to feel the pressure and anxiety of your actual examination one month earlier than the actual exam date.

·       You can’t predict the probability of selection but can try to minimize the possible errors. Remember, Failure in one exam is not the end of the world. This journey will make you a better version of yourself in every way.

·       I also believe that Luck has a very significant role in your selection especially when it’s about a margin of 2-3 marks, so don’t get bogged down in such cases. Prepare yourself for the next target.

·       In Case, you are confused about the existence of plan B, I advise you to give one full-fledged attempt without any plan B. After that, if the results are not in your favor, you can go either for Research through GATE, CSIR Net, or can prepare for other competitive exams such as RBI Grade B along with your preparation of ISS. In case you are interested in any specific field like Machine learning, you can go for Online courses available on Coursera, edX, etc, and take up a job in a recognized company. (Along with the preparation of ISS, I also prepared for various other exams such as RBI Grade B, DSSSB Statistical assistant, ICAR Net, GATE, and any other exams related to Statistics during the period. I have also done two Online courses related to the Subject. I enrolled in an internship with CSIR-CDRI after my First attempt. I worked as a Teaching Assistant in the Indian Institute of Management, Lucknow on a contractual basis after my second attempt. After that I joined the Ph.D. program from the Indian Institute of Bombay in January 2021 through GATE.)

·       Every Variable you introduce into a model can add information but also brings its own baggage. Considering your model, stay away from such variables who always try to let you down.

·       In case you feel demotivated after your first attempt or a mock test, sit calmly and analyze that where you are going wrong. Talking about improvement, I am sharing the mark sheet of my two failed attempts.


·       Last but not least, if you have given any unprepared attempt (just to take an idea of the examination) and analyzed your strength and weaknesses through the Marksheet of that attempt, please don’t do it. The reason is that when you will give your sincere attempt, there will be a lot of pressure and nervousness about the exam. You can’t feel that pressure on the day of your unprepared attempt. It may be possible that you have performed well in certain papers because you have no pressure to be selected on the back of your mind. This is a psychological fact that when you are serious about your exam and invested almost a year for preparation, you may forget some basic things due to pressure on the day of your exam. (I appeared in one such unprepared attempt and got 28 marks in English after attempting 40 marks questions. I thought there is no need to pay attention to this paper much as I have already scored well. But that was my mistake which made me unable to clear the cutoff in my first sincere attempt)

My Mistakes –  

In my first attempt, I worked very hard but could not study the syllabus in a planned way. Also, I took the General English paper very lightly. I did not analyze myself through mock tests and believed that after studying any topic, I can recall it easily in the exam. Apart from that, I did not make any notes for revision. Hence, I could not simulate the pressure of the exam before my real exam. Also, I did not take proper sleep during the exam which badly affected my performance.

In my second attempt, I tried to correct my mistakes. I expected a lot from myself and thought that anyhow I have to perform very well especially in my Descriptive papers. Somehow, the third paper of the year 2019 was a little bit tough (as per the PYQ’s) Since I already expected a lot from that paper, I got nervous in those 3 hours and could not do those questions which I knew. As a result, I scored very low marks on that paper, hence could not clear the written cutoff.

In my third attempt, I did not do anything special. I just tried to maintain a healthy routine and keep myself calm before the exam. Understanding the importance of small things helped me in a big way.





Concluding Remark –This Preparation requires Mental calmness, Discipline, and Stability 24/7. When I got failed in two attempts consecutively, I felt highly demotivated. Along with the support of My Mentor, family, friends, the blog written by IAS Anudeep Durishetty Sir really helped me a lot. You can read it from here

(** Views are personal, please don’t follow the above-mentioned strategy blindfold. Take the things from your perspective)

In case you want to ask anything regarding preparation, you can directly contact me on my email id-






































  1. GREAT CONTRIBUTION for upcoming ones , one can learn different phases of life and keep performing honest work despite of many ups and downs.

  2. Great!!! Amazingly well put together blog covering all the details. Many more achievements waiting to come your way.. 😇👏👏

  3. Thank you ma'am for sharing this 🙌🙌

  4. Thanku maam for sharing this. It is really helpful .


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