Mathematical and statistical analysis of the 19th round of the Spanish Segunda RFEF – Group 3 (Season 2025-2026): “Kara” Protocol

Description

Mathematical and statistical analysis of the 19th round of the Spanish Segunda RFEF – Group 3 (Season 2025-2026): “Kara” Protocol

Introduction to the strategic framework of the Segunda RFEF

The Spanish Segunda RFEF, better known as the Segunda Federación, is the fourth tier of Spanish football and is divided into five geographical groups. ¹ Group 3, which includes teams mainly from Catalonia, the Balearic Islands and the Valencian Community, is known for its tactical intensity and high level of competition. ³ By the 19th round of the 2025–2026 season, the league is entering its critical phase – the start of the second half of the season, where mistakes become increasingly costly for teams fighting for promotion or survival. ⁵

This report rigorously applies the computational protocol “Kara” to decipher the hidden patterns in the statistics of the 18 teams. The “Kara” model is not just a prediction tool; it is a risk assessment system that, through the Harmony Index, helps identify events with a mathematical advantage over market odds. ⁷ In the context of the 19th round, where affiliate teams such as Barcelona B, Valencia B and Espanyol B frequently change their lineups depending on the needs of the first teams, mathematical discipline is essential to avoid emotional traps in betting. ⁸

Description of the mathematical calculation protocol

The Kara protocol is based on a nine-step methodology that transforms raw statistics into objective probabilities. Each step is designed to filter out the “noise ” and focus on the structural strengths of the participants. ⁷

First and second calculation: Input data and attack strength

The process begins by extracting five key parameters for each team: win percentage ( W% ), draw percentage (D%), loss percentage (L%), goals scored (GF), and goals conceded (GA). ⁷ These data are calculated based on all matches played since the start of the championship to ensure a representative sample.

The attack power ($Atk$) is defined by the formula:

$$Atk = W _{ dec} + L_{dec} + GF_{avg}$$

where $W_{dec}$ and $L_{dec}$ are the win and loss percentages, respectively, converted to decimals, and $GF_{avg}$ is the average number of goals scored per match.7 This formula does not simply measure goal-scoring ability, but the team’s overall aggressiveness and ability to impose its will in matches.

Third and fourth calculation: Defense strength and expected goals (xG)

Defensive strength ($Def$) is the reciprocal of the delta between wins and losses, adjusted for goals conceded ($GA _{ avg}$) 7:

$$Def = \frac{1}{W_{dec} – L _{ dec} + GA_{avg}}$$

A low value here indicates vulnerability, while a high value signals defensive stability.

The expected goals ($xG$) for a given match are calculated by averaging the attack of one team and the defense of its opponent.7 In this way, the model simulates the clash of the two opposing forces on the field:

$$xG _{ Home} = \frac{Atk_{Home} + Def_{Away}}{2}$$

$$xG _{ Away} = \frac{Atk_{Away} + Def_{Home}}{2}$$

Fifth to Eighth Calculation: Poisson, Stability, and Harmony Index

The probabilities for the final outcome (1, X, 2) are generated using a Poisson distribution based on the resulting $xG$ values.7 The Stability Index ($K$) is then applied, which uses the standard deviation of the probabilities to determine how confident the model is in its prediction.7 The final score is given by the Harmony Index:

$$Harmony = \ left( \frac{2}{K}\right) + \left(\frac{1}{1 – L}\right)$$

where $L$ is the equality index, measuring the absolute difference in the attack/defense balance between the two teams.7

Analysis of the standings and current trends after 18 matches

Before we move on to the individual matches, it is necessary to look at the overall picture in Group 3. Poblense leads the standings with 36 points, closely followed by Reus FC Redis (33) and Atletico Baleares (32). ⁸ These three teams are the main contenders for direct promotion.

Pos.	Team	M	P	P	H	G	GR	T
1	Poblense	18	10	6	2	24:11	+13	36
2	Reus FC Redis	18	10	3	5	32:20	+12	33
3	Atlético Baleares	18	9	5	4	27:23	+4	32
4	Sant Andreu	18	9	4	5	25:18	+7	31
5	Barcelona B	18	8	5	5	38:25	+13	29
6	Alcoyano	18	7	8	3	17:13	+4	29
7	Terrace	18	7	7	4	24:23	+1	28
8	SD Ibiza	18	7	4	7	16:20	-4	25
9	Espanyol B	18	5	9	4	19:16	+3	24
10	Girona B	18	6	5	7	21:19	+2	23
11	Valencia B	18	5	7	6	26:30	-4	22
12	Olot	18	4	8	6	14:17	-3	20
13	Andrach	18	5	5	8	19:23	-4	20
14	Castellon B	18	5	5	8	30:42	-12	20
15	Barbastro	18	4	6	8	14:19	-5	18
16	Porreres	18	3	6	9	10:19	-9	15
17	Athletic Lleida	18	2	8	8	21:30	-9	14
18	Torrent	18	2	7	9	19:28	-9	13

Source: ⁸

The average score in the group is relatively high for this level of football, with Barcelona B and Castellón B being the teams with the most goals in their matches. ³ It should be noted that Poblense’s defensive line is the most stable, conceding only 0.61 goals per match, which is a fundamental prerequisite for their leading position. ⁴

Detailed analysis of the matches from the 19th round

1. Castellon B vs Athletic Lleida

Date: January 17, 2026 , 5:00 p.m.

Odds: 2.24 (1), 3.67 (X), 2.64 (2) [User Image]

This match pits two teams from the bottom third of the table against each other. Castellón B is a “two-faced ” team – they have the second best attack among the affiliates (30 goals), but at the same time they have the weakest defense in the entire league (42 goals conceded). ⁸ Athletic Lleida are on a streak of draws and are having difficulties on their away games. ⁴

Calculations under the Kara Protocol:

• Step 1 (Base – Castellon B): W%: 27.8%; D%: 27.8%; L%: 44.4%; GF: 1.67; GA: 2.33.
• Step 1 (Base – Athletic Leyda): W%: 11.1%; D%: 44.4%; L%: 44.4%; GF: 1.17; GA: 1.67.
• Step 2 (Attacking force):
  • Castellon B: $0.278 + 0.444 + 1.67 = $2.392.
  • Athletic Leyda: $0.111 + 0.444 + 1.17 = $1.725.
• Step 3 (Protective force):
  • Castellon B: $1 / (0.278 – 0.444 + 2.33) = 1 / 2.164 = $0.462.
  • Athletic Leyda: $1 / (0.111 – 0.444 + 1.67) = 1 / 1.337 = $0.748.
• Step 4 (xG values):
  • xG Home = $(2.392 + 0.748) / 2 = $1.57.
  • xG Guest = $(1.725 + 0.462) / 2 = $1.09.
• Step 5 (Probabilities): 1: 46%; X: 24%; 2: 30%.
• Step 6 (Stability K): 0.43.
• Step 7 (L Equality Index): 0.38.
• Step 8 (Harmony Index): 6.26.
• Step 9 (Verdict V3): $0.46 – 0.30 = $0.16 (Prediction: 1).

Analysis: Despite the low ranking of the home team, their offensive power is significantly higher than that of the visitors. Athletic Leyda rely on a defensive game, but against a team that scores an average of 1.67 goals, they will be under serious pressure. ¹⁴ Harmony Index is low, indicating a risk of surprise due to Castellon B’s leaky defense.

2. Barcelona B vs. Andratx

Date: January 17, 2026 , 7:15 p.m.

Odds: 1.44 (1), 4.10 (X), 6.08 (2) [User Image]

This is one of the most unequal matches in the round according to market estimates. Barcelona B (Barça Atlètic) has the best attack in the group (38 goals in 18 matches) and plays at their own Johan Cruyff Stadium. ¹⁵ Andrac are a typical midfield player who relies on a compact game, but often cracks against technical teams. ⁴

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Barcelona B: $0.444 + 0.278 + 2.11 = $2.832.
  • Andrach: $0.278 + 0.444 + 1.06 = $1.782.
• Step 3 (Protective force):
  • Barcelona B: $1 / (0.444 – 0.278 + 1.39) = 1 / 1.556 = $0.643.
  • Andrach: $1 / (0.278 – 0.444 + 1.28) = 1 / 1.114 = $0.898.
• Step 4 (xG values):
  • xG Home = $(2.832 + 0.898) / 2 = $1.87.
  • xG Guest = $(1.782 + 0.643) / 2 = 1.21$.
• Step 5 (Probabilities): 1: 52%; X: 22%; 2: 26%.
• Step 6 (Stability K): 0.36.
• Step 8 (Harmony Index): 7.15.
• Step 9 (Verdict V3): $0.52 – 0.26 = 0.26$ (Prediction: 1).

Analysis: Barcelona B are the favorites in all respects. Their xG of 1.87 is one of the highest in the round. ¹⁶ However, the low defense of the affiliate ($Def = 0.643$) means that Andrac could get a goal. ¹⁸ The match is categorized as “High Confidence ” due to the dominant attack of the home team.

3. Girona B vs Atletico Baleares

Date: January 18, 2026 , 1:00 p.m.

Odds: 2.93 (1), 3.21 (X), 2.24 (2) [User Image]

A clash between two teams with different ambitions. Girona B are in mid-table and in a shaky form. ⁴ Atletico Baleares is one of the big names in the group and is fighting for the top spot. ⁵ The market slightly favors the visitors, but the home advantage in Spain often evens things out.

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Girona B: $0.333 + 0.389 + 1.17 = $1.892.
  • Balearic Islands: $0.500 + 0.222 + 1.50 = $2.222.
• Step 3 (Protective force):
  • Girona B: $1 / (0.333 – 0.389 + 1.06) = $1,000.
  • Balearic Islands: $1 / (0.500 – 0.222 + 1.28) = $0.643.
• Step 4 (xG values):
  • xG Home = $(1.892 + 0.643) / 2 = $1.27.
  • xG Guest = $(2.222 + 1.000) / 2 = 1.61$.
• Step 5 (Probabilities): 1: 31%; X: 25%; 2: 44%.
• Step 6 (Stability K): 0.38.
• Step 9 (Verdict V3): $0.31 – 0.44 = -0.13$ (Prediction: X2).

Analysis: Atletico Baleares have the more experienced squad and this is reflected in their higher attacking power ($2.222$). ⁹ Girona B, however, has a more solid defensive metric ($1.000$ vs. $0.643$), which could lead to tactical outsmarting. ¹⁹ The X2 prediction is mathematically sound.

4. Olot vs. Poblense

Date: January 18, 2026 , 1:00 p.m.

Odds: 2.50 (1), 2.67 (X), 3.06 (2) [User Image]

Leader Poblense are away to Olot. Interestingly, bookmakers give the advantage to the host Olot, even though they are in 12th place and Poblense are first. ⁴ This is due to the fact that Olot is a very difficult team to beat at home (8 draws). ⁵

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Olot: $0.222 + 0.333 + 0.78 = $1.335.
  • Poblense: $0.555 + 0.111 + 1.33 = $1.996.
• Step 3 (Protective force):
  • Olot: $1 / (0.222 – 0.333 + 0.94) = $1.205.
  • Poblense: $1 / (0.555 – 0.111 + 0.61) = $0.949.
• Step 4 (xG values):
  • xG Home = $(1.335 + 0.949) / 2 = $1.14.
  • xG Guest = $(1.996 + 1.205) / 2 = $1.60.
• Step 5 (Probabilities): 1: 29%; X: 26%; 2: 45%.
• Step 9 (Verdict V3): $0.29 – 0.45 = -0.16$ (Prediction: X2).

Analysis: The “Cara ” model strongly disagrees with the market odds. Poblense have a better attack and an xG of 1.60. ⁴ Olot score too little (0.78 per game) to be considered a favorite against the leader. ¹⁷ Here we have a “Value bet” for Poblense.

5. Porreres vs Valencia B

Date: January 18, 2026 , 1:00 p.m.

Odds: 3.26 (1), 3.14 (X), 2.10 (2) [User Image]

Porreres is among the tail-enders and has serious problems with scoring goals (only 10 goals in 18 matches). ⁸ Valencia B (Valencia-Mestalla) are unpredictable, but have some of the best young talent in Spain. ¹⁷

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Porreres: $0.167 + 0.500 + 0.56 = $1.227.
  • Valencia B: $0.278 + 0.333 + 1.44 = $2.051.
• Step 3 (Protective force):
  • Porreres: $1 / (0.167 – 0.500 + 1.06) = $1.375.
  • Valencia B: $1 / (0.278 – 0.333 + 1.67) = $0.619.
• Step 4 (xG values):
  • xG Home = $(1.227 + 0.619) / 2 = 0.92$.
  • xG Guest = $(2.051 + 1.375) / 2 = 1.71$.
• Step 5 (Probabilities): 1: 19%; X: 26%; 2: 55%.
• Step 6 (Stability K): 0.49.
• Step 8 (Harmony Index): 9.42.
• Step 9 (Verdict V3): $0.19 – 0.55 = -0.36$ (Prediction: 2).

Analysis: This is a match with one of the biggest differences in xG (0.92 vs. 1.71). ¹¹ Porreres are defensively solid ($Def = 1.375$), but without an attack they will have a hard time winning. Valencia B are the favorite and the prediction is a clean even. ¹⁹

6. Terrace opposite SD Ibiza

Date: January 18, 2026 , 1:00 p.m.

Odds: 1.95 (1), 3.09 (X), 3.78 (2) [User Image]

Terrassa is in the top half of the table and is a traditionally strong home team. ⁴ SD Ibiza (Islas Pitiusas) are a defensive team that plays well on counterattacks. ⁴

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Terrace: $0.389 + 0.222 + 1.33 = $1.941.
  • SD Ibiza: $0.389 + 0.389 + 0.89 = $1.668.
• Step 3 (Protective force):
  • Terrace: $1 / (0.389 – 0.222 + 1.28) = $0.691.
  • SD Ibiza: $1 / (0.389 – 0.389 + 1.11) = $0.900.
• Step 4 (xG values):
  • xG Home = $(1.941 + 0.900) / 2 = $1.42.
  • xG Guest = $(1.668 + 0.691) / 2 = $1.18.
• Step 5 (Probabilities): 1: 43%; X: 27%; 2: 30%.
• Step 9 (Verdict V3): $0.43 – 0.30 = $0.13 (Prediction: 1).

Analysis: Terrassa has the advantage in attack, but Ibiza is a disciplined team. ¹⁹ The match looks like a low-scoring one, but the hosts have a little more arguments for the victory.

7. Torrent vs. Sant Andreu

Date: January 18, 2026 , 1:00 p.m.

Odds: 3.42 (1), 3.31 (X), 1.98 (2) [User Image]

Torrent is in last place and is in critical shape. ⁴ Sant Andreu is one of the most stable teams in the group and occupies 4th place. ¹⁰ The guests are favorites and the statistics confirm it.

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Torrent: $0.111 + 0.500 + 1.06 = $1.671.
  • Sant Andreu: $0.500 + 0.278 + 1.39 = $2.168.
• Step 3 (Protective force):
  • Torrent: $1 / (0.111 – 0.500 + 1.56) = $0.854.
  • Sant Andreu: $1 / (0.500 – 0.278 + 1.00) = $0.818.
• Step 4 (xG values):
  • xG Home = $(1.671 + 0.818) / 2 = $1.24.
  • xG Guest = $(2.168 + 0.854) / 2 = 1.51$.
• Step 5 (Probabilities): 1: 32%; X: 26%; 2: 42%.
• Step 9 (Verdict V3): $0.32 – 0.42 = -0.10$ (Prediction: X2).

Analysis: Sant Andreu has a higher offensive power ($2.168$) and a better defense. ¹¹ Torrent are fighting for survival, but the class of the visitors should prevail in this clash. ¹⁹

8. Barbastro vs. Alcoyano

Date: January 18, 2026 , 1:00 p.m.

Odds: 2.77 (1), 2.92 (X), 2.48 (2) [User Image]

A match between two teams that love draws. Alcoyano has 8 draws and one of the strongest defenses in the group. ⁴ Barbastro plays closed and relies on episodic counterattacks. ⁵

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Barbastro: $0.222 + 0.444 + 0.78 = $1.446.
  • Alcoyano: $0.389 + 0.167 + 0.94 = $1.496.
• Step 3 (Protective force):
  • Barbastro: $1 / (0.222 – 0.444 + 1.06) = $1.193.
  • Alcoyano: $1 / (0.389 – 0.167 + 0.72) = $1.061.
• Step 4 (xG values):
  • xG Home = $(1.446 + 1.061) / 2 = $1.25.
  • xG Guest = $(1.496 + 1.193) / 2 = $1.34.
• Step 5 (Probabilities): 1: 34%; X: 28%; 2: 38%.
• Step 7 (Equality Index L): 0.08.
• Step 8 (Harmony Index): 4.35.
• Step 9 (Verdict V3): $0.34 – 0.38 = -0.04$ (Prediction: X).

Analysis: All the indicators here scream for a draw. The xG difference is minimal (0.09) and the Draw Index is extremely low (0.08). ²² Alcoyano are masters of 0-0 and 1-1 results. ²³

9. Espanyol B vs Reus FC Redis

Date: January 18, 2026 , 5:15 p.m.

Odds: 2.23 (1), 2.92 (X), 3.22 (2) [User Image]

The derby of the round. Espanyol B is the king of draws (9 counts), while Reus FC Redis is in exceptional form and occupies 2nd place. ⁵ However, the bookmakers give the advantage to the home team, which is strange statistically.

Calculations under the Kara Protocol:

• Step 2 (Attacking force):
  • Espanyol B: $0.278 + 0.222 + 1.06 = $1.560.
  • Reus FC Reddys: $0.555 + 0.278 + 1.78 = $2.613.
• Step 3 (Protective force):
  • Espanyol B: $1 / (0.278 – 0.222 + 0.89) = $1.057.
  • Reus FC Reddys: $1 / (0.555 – 0.278 + 1.11) = $0.720.
• Step 4 (xG values):
  • xG Home = $(1.560 + 0.720) / 2 = $1.14.
  • xG Guest = $(2.613 + 1.057) / 2 = 1.83$.
• Step 5 (Probabilities): 1: 22%; X: 24%; 2: 54%.
• Step 6 (Stability K): 0.49.
• Step 8 (Harmony Index): 9.15.
• Step 9 (Verdict V3): $0.22 – 0.54 = -0.32$ (Prediction: 2).

Analysis: Here we have a huge disparity between market expectations and statistical reality. Reus FC Redis have crushing attacking power ($2.613$) against Espanyol B. ⁴ The prediction is a solid pair with a high Harmony Index, making it a “High Confidence” match. ²⁴

Summary results and match categorization

After the precise application of the nine calculations under the “Kara” Protocol, we can synthesize the data into the following final prediction table for the 19th round of the Segunda RFEF – Group 3.

Meeting	Predicted goals (xG)	Predicted outcome	Verdict (V3)	Category	Coefficient
Castellon B – Athletic Leyda	1.57 : 1.09	1	0.16	Standard	2.24
Barcelona B – Andrach	1.87 : 1.21	1	0.26	High Confidence	1.44
Girona B – Baleares	1.27 : 1.61	2	-0.13	Standard	2.24
Olot – Poblense	1.14 : 1.60	2	-0.16	Standard	3.06
Porreres – Valencia B	0.92 : 1.71	2	-0.36	High Confidence	2.10
Terrace – SD Ibiza	1.42 : 1.18	1	0.13	Standard	1.95
Torrent – Sant Andreu	1.24 : 1.51	X2	-0.10	Standard	1.35*
Barbastro – Alcoyano	1.25 : 1.34	X	-0.04	Draw Speculation	2.92
Espanyol B – Reus Reddis	1.14 : 1.83	2	-0.32	High Confidence	3.22

*The X2 odds are calculated as a derivative of the 1X2 market.

Special selections for the round

Based on the Harmony Index and deviations from market odds, the following matches stand out:

1. Platinum Selection: There is no match with a Harmony Index above 100 for this round, as the stability of results in this group is lower due to the volatility of the affiliate teams. ⁷
2. High Confidence:
   • Barcelona B – Andrac (Prediction 1): Huge attacking power and home advantage. ¹⁶
   • Porreres – Valencia B (Prediction 2): The guests are the classier team, and the hosts have a serious goal deficit. ¹¹
   • Espanyol B – Reus Redis (Prediction 2): The highest value in the round, based on the huge statistical advantage of the visitors. ¹²

Conclusion and strategic recommendations

The analysis of the 19th round reveals several critical points. The bookmakers seem to be underestimating leaders Poblense and Reus FC Redis on their away trips, probably relying on the “tie” factor, which is very strong in this group. ³ However, the “Kara” protocol clearly shows that the attacking power of these teams is structurally stronger than the defensive barriers of their hosts.

When betting on this round, users should pay attention to the following factors:

• Branch Dependency: Keep an eye on the Barcelona B and Valencia B squads as their xG value is highly dependent on the availability of their main scorers. ⁹
• Draw Index: In matches like Barbastro – Alcoyano, where $L$ is below 0.10, betting on a draw is a mathematically justified risk. ⁷
• Discipline: Always follow the Harmony Index, not your emotions. If the index is low, as in Castellon B, reduce your bet size, regardless of the predicted outcome. ⁷

As your betting guardian angel, Kara advises you to approach the bottom-of-the-table matches with caution, where survival motivation often trumps pure statistics. Good luck in Round 19!