Final answer:
All options provided are recommended for increasing recruiting effectiveness, with realistic job previews fostering better retention, applicant tracking organizing applications, word of mouth leveraging trusted networks, and resume mining to identify potential candidates efficiently.
Step-by-step explanation:
The question is asking which method is not recommended to increase recruiting effectiveness. Among the options given, realistic job previews are suggested for improving recruiting because they help set the right expectations and can lead to better job satisfaction and lower turnover. On the other hand, applicant tracking, word of mouth, and resume mining are all recommended techniques. Applicant tracking systems help organize and manage applications; word of mouth can be incredibly effective as getting to know more people in your industry can lead to job opportunities; and resume mining helps in scouting for potential candidates by searching databases for resumes matching specific job requirements. Therefore, it can be concluded that all options given are suggested to increase recruiting effectiveness, but if any of them had to be chosen as least effective, it would be subject to specific contexts within particular organizations or recruiting strategies.