Final answer:
In the analysis and investigation stage of human resource planning, key sources of information include in-depth interviews, focus groups, analysis of content sources, and quantitative data.
Step-by-step explanation:
The key sources of information that are analyzed during the analysis and investigation stage of human resource planning include in-depth interviews, focus groups, analysis of content sources, quantitative data, observation, surveys, and interviews. In-depth interviews and focus groups allow HR professionals to gather insights and perspectives from employees, managers, and other stakeholders. Analysis of content sources involves examining documents, reports, policies, and other relevant materials. Quantitative data provides statistical information on factors such as employee performance, turnover rates, and workforce demographics. Observation, surveys, and interviews are used to gather information on job requirements and skills.