# Analyzing Port State Control Data to Explore Future Improvements to GMDSS Training
## 4 Discussion  
### Which Criterion Best Highlights the Worst Performance in Communications Safety of Inspected Ships? Various authors also highlight that the number of deficiencies and the number of detentions in the last 36 months serve as risk indicators, for example [48]. However, in the study carried out, it was revealed that the number of times a ship repeats a radio inspection throughout any period considered is a better estimator of risk than the number of deficiencies found. In fact, the number of deficiencies may indicate a tendency to decrease, while inspections with deficiencies are still present in the analyzed time history. It must be taken into account that, regarding the period of time considered for the evaluation, the longer the better. The variability of the number of inspections over time and the variation of the time elapsed between two inspections will be studied. In the records, the 10 ships that showed the worst performance using the subset HRSC1, the relationship (a/b) between (a) the extension in years detecting problems in the GMDSS of ships (the first and the last year), respect to (b) the number of years in which at least one inspection is detected is 11/10, 13/11, 16/8, 13/9, 14/8, 13/9, 15/10, 8/6, 16/10, 13/8 (in total 132/89), while in the subset HRSC4, the ratio (a/b) is 15/5, 4/3, 10/6, 11/8, 13/8, 3/3, 1/1, 14/4, 4/4, 8/5 (in total 83/47). The temporal prevalence of the subset HRSC1 is higher than that of HRSC4. Care has been taken to eliminate those ships that appear in both groups (four in this case), which will allow their differences to be better appreciated. In these 10 ships of the subset HRSC1, 20 inspections that were conducted to detention and 50 inspections that include failures that have been labeled as due to poor training in this study have been detected. When subset HRSC4 is examined, these quantities drop to 9 and 38, respectively. There is no big difference when comparing the average ages of ships when using the age of the first inspection carried out in the records (28.7 vs. 27.5 years). Regarding the composition of flags and types of ships, interesting differences are evident. The relationship between the 10 worst-performing ships in the subset HRSC1 and HRSC4 about the flags is 8 ships against 3 within the blacklist, and about the type of ship, 9 against 3 are cargo ships and 1 against 6 are passenger ships. Certain studies have used as an indicator of the effectiveness of inspections the number of deficiencies found after several successive inspections that used to exhibit a negative trend [49,50]. Also, a causal relationship is established between the time elapsed between two inspections, the age of the ship, the type of ship, and the registration flag as predictors [50]. This document shows that the number of repetitions of inspections per sampling period (in this study, 1 year has been used) is a more consistent indicator since it shows the prevalence of the problem, and also that the subset HRSC1 fits better to a model than the rest of the proposals set out in Section 2.2. Relationship between Explanatory Variables and Radio Inspections That Lead to the Detention of the Vessel  
It is well known that data from PSC inspections allow for characterizing the influence of the ship's static risk factors, such as the type of ship, age, and flag, on the safety level of ships. Much detailed analysis of PSC inspection records proves that the age of the ship was the most important factor in predicting ship quality [15; 47; 51] followed by other ship attributes: Ship type, flag [15; 47; 48; 51], and ship inspection history [47; 48]. The study of the impact of the combination of factors is also of interest. For example, cargo vessels and vessels on the black list are ships with the highest probability of problems in the inspections [47; 51], and the combination age/tonnage/ship type (more than 20 years/less than 5000 tons/and cargo vessel) are characteristics influencing the probability of detention [15]. Tankers are situated on the opposite side of the safety scores.