Generally, the IRS can include returns filed within the last three years in an audit.
The IRS does not contact an individual via e-mail for an initial appointment. Contact related to being selected for an audit will be made via mail only, due to disclosure requirements.
Filing an amended return does not affect the selection process of the original return. However, amended returns also go through a screening process and the amended return may be selected for audit.
When returns are filed, they are compared against “norms” for similar returns. The “norms” are developed from audits of a statistically valid random sample of returns. These returns are selected as part of the National Research Program which the IRS conducts to update return selection information.