The methods are ranked based on their effectiveness in rendering data irrecoverable.

1. Destruction is the most effective method as it physically destroys the media (e.g., through shredding, pulverizing, or incineration), making data recovery impossible.
2. Degaussing is the next best, using a powerful magnetic field to neutralize the magnetic alignment on the media, effectively erasing the data and making it infeasible to recover even with advanced laboratory techniques.
3. Overwriting involves writing new patterns of data over the original data. While effective against simple recovery tools, sophisticated forensic methods might still be able to recover data remnants.
4. Deleting is the least effective method. It typically only removes the file's pointer from the file system's index, leaving the actual data on the disk until it is overwritten by new files. This data is easily recovered with common software.

NIST Special Publication 800-88 Rev. 1, Guidelines for Media Sanitization. This standard defines the hierarchy of sanitization methods.

Section 2.4, "Destruction": Describes methods like disintegration, pulverization, melting, and incineration as the ultimate form of sanitization. "Destruction of media is the most secure method of sanitization." (Page 8).

Section 2.3, "Purge": Defines Purge techniques, including Degaussing, as rendering data recovery "infeasible using state of the art laboratory techniques." (Page 8).

Section 2.2, "Clear": Defines Clear techniques, including Overwriting, as applying "logical techniques to sanitize data in all user-addressable storage locations for protection against simple non-invasive data recovery techniques." (Page 7). Standard file deletion is explicitly noted as not being a sufficient method of clearing.

Garfinkel, S., & Rosen, R. (2015). A Guide to Understanding Data Remanence in Automated Information Systems. National Institute of Standards and Technology.

Section 3.1, "Data Deletion versus Media Sanitization": "Deleting a file on a typical file system is a simple, fast operation. In most cases, the operation simply removes the directory entry for the file and returns the file’s allocated blocks to the pool of free space... the file’s data blocks are not actually modified in any way and could be recovered." (Page 9). This confirms 'Deleting' as the least secure option.

Zhi, L. (2010). A new approach to information security of computer hard disk. 2010 2nd IEEE International Conference on Information Management and Engineering. https://doi.org/10.1109/ICIME.2010.5477465

Section III, "Common Methods of Hard Disk Information Security": This paper reviews common methods and implicitly ranks their security. It describes physical destruction as providing "the highest security degree," degaussing as a "reliable secure erasure method," and overwriting as a method that can be defeated by specialized equipment, placing them in the same hierarchy as the NIST standard.