Table 2 Inclusion–exclusion criteria for review methods

Inclusion 1: A study that is published in the trustful recommendation in the IoT field

We precisely examine how trust evaluation affects either reliability in IoT or indirectly assesses recommendation accuracy in this scenario

Inclusion 2: A study that is directed either by academics or practitioners

Both academic and industrial solutions are taken into account

Inclusion 3: A study that is peer-reviewed

This standard guarantees a precise quality level and a considerable amount of content

Inclusion 4: A study that is written in English

For suitability, we excluded papers published in other languages rather than English

Inclusion 5: Date of data extraction

From 2011 to December 2018

Exclusion 1: A study that made part of journals

Conference papers, doctoral dissertations, books, editorial notes, and unpublished papers were not involved, as researchers commonly refer journals to obtain and disperse information

Exclusion 2: A study that developed diverse recommendation mechanisms on the Internet

Only recommendation mechanism in the IoT is relevant to this study

Exclusion 3: Duplicate copies of exactly like study

Various reports of a study are in differing journals, the most thoroughgoing issues included