EBolinVA / Pewlett-Hackard-Analysis

Using SQL to query employee data to forecast retirements and employment needs

Pewlett-Hackard-Analysis

📖 Table of Contents

1. About the Project
2. Prerequisites
3. Dataset
4. Queries
5. Results and Discussion
6. Recommendations

📝 About the Project

This project uses SQL to query employee data for Pewlett Hackard. They anticipate a changing workforce and want to forecast retirements and employment needs. Many job openings are imminent due to baby boomers in the workforce retiring. Our data analysis goal is to forecast the departments and positions that will need filling, and also find the group of junior employees who can be mentored into new roles.

Working with an original data set of 6 .csv files holding employee, department, manager, title, and salary information, the first task is to create an entity relationship diagram (ERD) to understand the schema of the database we are building.

The next task is to join and create new tables in a relational database with more targeted information about those employees currently eligible for retirement. Using the query tool in pgAdmin4 platform enables quick results and clean data.

schema.sql file: Creating tables to load the original data for our database using PostgreSQL in pgAdmin4.

💼 Prerequisites

The following open source packages are used in this project:

• QuickDBD
• 
• pgAdmin 4

💾 Dataset

The dataset includes human resources information obtained from Pewlett Hackard in December 2022, and consists of six original .csv files:

• employees
• departments
• dept_manager
• dept_employee
• salaries
• titles

❓ Queries

• How many are eligible to retire?

First we need determined the number of retiring employees per job title. The employees.csv file holds over 300,000 records with employee number (emp_no), birth date, name, gender and hire date.

--Retirement eligibility

SELECT first_name, last_name
FROM employees
WHERE (birth_date BETWEEN '1952-01-01' AND '1955-12-31');

The above query did not take into consideration the to_date, which is the date that indicates whether an employee is still currently working at Pewlett Hackard. The 'to_date' column is found in the original dept_emp.csv file. The next query includes the line of code:

WHERE de.to_date = ('9999-01-01');

Setting the to_date to January 1, 9999, ensures that the query returns only retirement eligible employees who are still on the payroll. This results in narrowing down the list of retirement eligible employees to 72,458.

• How many employees are eligible for mentorship?

SELECT DISTINCT ON(e.emp_no) e.emp_no,
	e.first_name, 
	e.last_name, 
	e.birth_date,
	de.from_date,
	de.to_date,
	t.title
--INTO mentorship_eligibility
FROM employees As e
LEFT JOIN dept_emp As de
ON e.emp_no = de.emp_no
LEFT JOIN titles As t
ON e.emp_no = t.emp_no
GROUP BY e.emp_no, de.from_date, de.to_date, e.birth_date, t.title
HAVING (de.to_date = '9999-01-01') 
	AND (e.birth_date BETWEEN '1965-01-01' AND '1965-12-31')
ORDER BY e.emp_no;

⚠️ Results and Discussion

• 240,124 Pewlett Hackard current employees
• 72,458 employees eligible to retire; 33,118 have at least 30 years of service
• 1,549 employees eligible for mentorship
• 30% reduction of workforce imminent due to retirement

🌊 Summary and Recommendations

The impending "silver tsunami" requires some planning to fill upcoming vacant positions. There are two main questions this analysis set out to address: the number of retiring employees and the number of those ready for mentorships.

* How many employees are currently eligible to retire?

• 72,458 employees are currently eligible to retire:
  • Join titles, dept_emp, and employees file to obtain current employees eligible to retire by birthdate between 1952 and 1955.

• There are 240,124 total employees. 30% (72,458) of Pewlett Hackard's workforce are about to retire.

* How many employees are currently eligible for mentorship?

• 1,549 employees are eligible for mentorship based on birth_date in 1965. Expand the pool of employees in mentorship to fill senior leadership:

  • Recommendation: widen the range of employees by including younger employees:

  • ❗ there are no employees in the database with a birth_date more recent than 1965-12-31

  • A query of current employees born after 1955 is done with the following code and results in 167,666 employee records:

  SELECT DISTINCT ON(e.emp_no) e.emp_no,
      e.first_name, 
      e.last_name, 
      e.birth_date,
      e.hire_date,
      de.from_date,
      de.to_date, 
      t.title
  FROM employees As e
  LEFT JOIN dept_emp As de
  ON e.emp_no = de.emp_no
  INNER JOIN titles As t
  ON e.emp_no = t.emp_no
  GROUP BY e.emp_no, e.hire_date, de.from_date, de.to_date, e.birth_date, t.title
  HAVING (de.to_date = '9999-01-01') AND (e.birth_date > '1955-12-31')
  ORDER BY e.emp_no;
  

• 167,666 current employees are younger than the retirement age employees.

  • Recommendations to expand mentorship pool:
    • choose mentorship by years of service without limiting it to 1965 DOB
    • create recent graduate pipeline to build up workforce